Lisa,

I've created a small demo console application:
Create a project folder on your drive c:\ in the following path:

C:\temp2\tester\

Then save the following files in that folder. The open the project in VS2005 and build it. Run it and you'll see what I mean.

Save this as Tester.csproj

<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProductVersion>8.0.50727</ProductVersion>
    <SchemaVersion>2.0</SchemaVersion>
    <ProjectGuid>{8F4AB357-49E6-4575-8478-94B0264987F9}</ProjectGuid>
    <OutputType>Exe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>Tester</RootNamespace>
    <AssemblyName>Tester</AssemblyName>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Data" />
    <Reference Include="System.Runtime.Remoting" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Program.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="test.cs" />
  </ItemGroup>
  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

Save below as program.cs

using System;
using System.Text;
using System.IO;
using System.Data;
using System.Xml;
using Tester;
using System.Runtime.Remoting.Metadata.W3cXsd2001;
namespace Tester
{
    public class Demo
    {
        public static void Main(string[] args)
        {
            Assignments myDataSet = new Assignments();
            myDataSet.ReadXml("c:\\temp2\\test.xml",XmlReadMode.Auto);
            SoapHexBinary hexBinary = new SoapHexBinary(myDataSet.Assignment[0].Payload);
            // Print the value of the SoapHexBinary object in XSD format. 
            Console.WriteLine("The SoapHexBinary object in XSD format is {0}.",
                hexBinary.ToString());
            Console.WriteLine();

            // Print the XSD type string of this particular SoapHexBinary object.
            Console.WriteLine(
                "The XSD type of the SoapHexBinary object is {0}.",
                hexBinary.GetXsdType());

            // Print the value of the SoapHexBinary object.
            Console.Write("hexBinary.Value contains:");
            Console.Write(hexBinary.ToString());
            Console.WriteLine();
            Console.WriteLine();
            for (int i = 0; i < hexBinary.Value.Length; ++i)
            {
            Console.Write(" " + hexBinary.Value[i]);
            }
            Console.WriteLine();

            // Print the XSD type string of the SoapHexBinary class.
            Console.WriteLine();
            Console.WriteLine("The XSD type of the class SoapHexBinary is {0}.",
                SoapHexBinary.XsdType);
        }
    }
}

Save below as test.cs, this is the dataset class:

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:2.0.50727.42
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

using System;
namespace Tester
{
    // 
    // This source code was auto-generated by xsd, Version=2.0.50727.42.
    // 


    [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Data.Design.TypedDataSetGenerator", "2.0.0.0")]
    [Serializable()]
    [System.ComponentModel.DesignerCategoryAttribute("code")]
    [System.ComponentModel.ToolboxItem(true)]
    [System.Xml.Serialization.XmlSchemaProviderAttribute("GetTypedDataSetSchema")]
    [System.Xml.Serialization.XmlRootAttribute("Assignments")]
    [System.ComponentModel.Design.HelpKeywordAttribute("vs.data.DataSet")]
    public partial class Assignments : System.Data.DataSet
    {

        private AssignmentDataTable tableAssignment;

        private System.Data.SchemaSerializationMode _schemaSerializationMode = System.Data.SchemaSerializationMode.IncludeSchema;

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        public Assignments()
        {
            this.BeginInit();
            this.InitClass();
            System.ComponentModel.CollectionChangeEventHandler schemaChangedHandler = new System.ComponentModel.CollectionChangeEventHandler(this.SchemaChanged);
            base.Tables.CollectionChanged += schemaChangedHandler;
            base.Relations.CollectionChanged += schemaChangedHandler;
            this.EndInit();
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected Assignments(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context)
            :
                base(info, context, false)
        {
            if ((this.IsBinarySerialized(info, context) == true))
            {
                this.InitVars(false);
                System.ComponentModel.CollectionChangeEventHandler schemaChangedHandler1 = new System.ComponentModel.CollectionChangeEventHandler(this.SchemaChanged);
                this.Tables.CollectionChanged += schemaChangedHandler1;
                this.Relations.CollectionChanged += schemaChangedHandler1;
                return;
            }
            string strSchema = ((string)(info.GetValue("XmlSchema", typeof(string))));
            if ((this.DetermineSchemaSerializationMode(info, context) == System.Data.SchemaSerializationMode.IncludeSchema))
            {
                System.Data.DataSet ds = new System.Data.DataSet();
                ds.ReadXmlSchema(new System.Xml.XmlTextReader(new System.IO.StringReader(strSchema)));
                if ((ds.Tables["Assignment"] != null))
                {
                    base.Tables.Add(new AssignmentDataTable(ds.Tables["Assignment"]));
                }
                this.DataSetName = ds.DataSetName;
                this.Prefix = ds.Prefix;
                this.Namespace = ds.Namespace;
                this.Locale = ds.Locale;
                this.CaseSensitive = ds.CaseSensitive;
                this.EnforceConstraints = ds.EnforceConstraints;
                this.Merge(ds, false, System.Data.MissingSchemaAction.Add);
                this.InitVars();
            }
            else
            {
                this.ReadXmlSchema(new System.Xml.XmlTextReader(new System.IO.StringReader(strSchema)));
            }
            this.GetSerializationData(info, context);
            System.ComponentModel.CollectionChangeEventHandler schemaChangedHandler = new System.ComponentModel.CollectionChangeEventHandler(this.SchemaChanged);
            base.Tables.CollectionChanged += schemaChangedHandler;
            this.Relations.CollectionChanged += schemaChangedHandler;
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        [System.ComponentModel.Browsable(false)]
        [System.ComponentModel.DesignerSerializationVisibility(System.ComponentModel.DesignerSerializationVisibility.Content)]
        public AssignmentDataTable Assignment
        {
            get
            {
                return this.tableAssignment;
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        [System.ComponentModel.BrowsableAttribute(true)]
        [System.ComponentModel.DesignerSerializationVisibilityAttribute(System.ComponentModel.DesignerSerializationVisibility.Visible)]
        public override System.Data.SchemaSerializationMode SchemaSerializationMode
        {
            get
            {
                return this._schemaSerializationMode;
            }
            set
            {
                this._schemaSerializationMode = value;
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        [System.ComponentModel.DesignerSerializationVisibilityAttribute(System.ComponentModel.DesignerSerializationVisibility.Hidden)]
        public new System.Data.DataTableCollection Tables
        {
            get
            {
                return base.Tables;
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        [System.ComponentModel.DesignerSerializationVisibilityAttribute(System.ComponentModel.DesignerSerializationVisibility.Hidden)]
        public new System.Data.DataRelationCollection Relations
        {
            get
            {
                return base.Relations;
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected override void InitializeDerivedDataSet()
        {
            this.BeginInit();
            this.InitClass();
            this.EndInit();
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        public override System.Data.DataSet Clone()
        {
            Assignments cln = ((Assignments)(base.Clone()));
            cln.InitVars();
            cln.SchemaSerializationMode = this.SchemaSerializationMode;
            return cln;
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected override bool ShouldSerializeTables()
        {
            return false;
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected override bool ShouldSerializeRelations()
        {
            return false;
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected override void ReadXmlSerializable(System.Xml.XmlReader reader)
        {
            if ((this.DetermineSchemaSerializationMode(reader) == System.Data.SchemaSerializationMode.IncludeSchema))
            {
                this.Reset();
                System.Data.DataSet ds = new System.Data.DataSet();
                ds.ReadXml(reader);
                if ((ds.Tables["Assignment"] != null))
                {
                    base.Tables.Add(new AssignmentDataTable(ds.Tables["Assignment"]));
                }
                this.DataSetName = ds.DataSetName;
                this.Prefix = ds.Prefix;
                this.Namespace = ds.Namespace;
                this.Locale = ds.Locale;
                this.CaseSensitive = ds.CaseSensitive;
                this.EnforceConstraints = ds.EnforceConstraints;
                this.Merge(ds, false, System.Data.MissingSchemaAction.Add);
                this.InitVars();
            }
            else
            {
                this.ReadXml(reader);
                this.InitVars();
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        protected override System.Xml.Schema.XmlSchema GetSchemaSerializable()
        {
            System.IO.MemoryStream stream = new System.IO.MemoryStream();
            this.WriteXmlSchema(new System.Xml.XmlTextWriter(stream, null));
            stream.Position = 0;
            return System.Xml.Schema.XmlSchema.Read(new System.Xml.XmlTextReader(stream), null);
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        internal void InitVars()
        {
            this.InitVars(true);
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        internal void InitVars(bool initTable)
        {
            this.tableAssignment = ((AssignmentDataTable)(base.Tables["Assignment"]));
            if ((initTable == true))
            {
                if ((this.tableAssignment != null))
                {
                    this.tableAssignment.InitVars();
                }
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        private void InitClass()
        {
            this.DataSetName = "Assignments";
            this.Prefix = "";
            this.Locale = new System.Globalization.CultureInfo("");
            this.EnforceConstraints = true;
            this.SchemaSerializationMode = System.Data.SchemaSerializationMode.IncludeSchema;
            this.tableAssignment = new AssignmentDataTable();
            base.Tables.Add(this.tableAssignment);
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        private bool ShouldSerializeAssignment()
        {
            return false;
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        private void SchemaChanged(object sender, System.ComponentModel.CollectionChangeEventArgs e)
        {
            if ((e.Action == System.ComponentModel.CollectionChangeAction.Remove))
            {
                this.InitVars();
            }
        }

        [System.Diagnostics.DebuggerNonUserCodeAttribute()]
        public static System.Xml.Schema.XmlSchemaComplexType GetTypedDataSetSchema(System.Xml.Schema.XmlSchemaSet xs)
        {
            Assignments ds = new Assignments();
            System.Xml.Schema.XmlSchemaComplexType type = new System.Xml.Schema.XmlSchemaComplexType();
            System.Xml.Schema.XmlSchemaSequence sequence = new System.Xml.Schema.XmlSchemaSequence();
            xs.Add(ds.GetSchemaSerializable());
            System.Xml.Schema.XmlSchemaAny any = new System.Xml.Schema.XmlSchemaAny();
            any.Namespace = ds.Namespace;
            sequence.Items.Add(any);
            type.Particle = sequence;
            return type;
        }

        public delegate void AssignmentRowChangeEventHandler(object sender, AssignmentRowChangeEvent e);

        [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Data.Design.TypedDataSetGenerator", "2.0.0.0")]
        [System.Serializable()]
        [System.Xml.Serialization.XmlSchemaProviderAttribute("GetTypedTableSchema")]
        public partial class AssignmentDataTable : System.Data.DataTable, System.Collections.IEnumerable
        {

            private System.Data.DataColumn columnPayload;

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentDataTable()
            {
                this.TableName = "Assignment";
                this.BeginInit();
                this.InitClass();
                this.EndInit();
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            internal AssignmentDataTable(System.Data.DataTable table)
            {
                this.TableName = table.TableName;
                if ((table.CaseSensitive != table.DataSet.CaseSensitive))
                {
                    this.CaseSensitive = table.CaseSensitive;
                }
                if ((table.Locale.ToString() != table.DataSet.Locale.ToString()))
                {
                    this.Locale = table.Locale;
                }
                if ((table.Namespace != table.DataSet.Namespace))
                {
                    this.Namespace = table.Namespace;
                }
                this.Prefix = table.Prefix;
                this.MinimumCapacity = table.MinimumCapacity;
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected AssignmentDataTable(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context)
                :
                    base(info, context)
            {
                this.InitVars();
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public System.Data.DataColumn PayloadColumn
            {
                get
                {
                    return this.columnPayload;
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            [System.ComponentModel.Browsable(false)]
            public int Count
            {
                get
                {
                    return this.Rows.Count;
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentRow this[int index]
            {
                get
                {
                    return ((AssignmentRow)(this.Rows[index]));
                }
            }

            public event AssignmentRowChangeEventHandler AssignmentRowChanging;

            public event AssignmentRowChangeEventHandler AssignmentRowChanged;

            public event AssignmentRowChangeEventHandler AssignmentRowDeleting;

            public event AssignmentRowChangeEventHandler AssignmentRowDeleted;

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public void AddAssignmentRow(AssignmentRow row)
            {
                this.Rows.Add(row);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentRow AddAssignmentRow(byte[] Payload)
            {
                AssignmentRow rowAssignmentRow = ((AssignmentRow)(this.NewRow()));
                rowAssignmentRow.ItemArray = new object[] {
                    Payload};
                this.Rows.Add(rowAssignmentRow);
                return rowAssignmentRow;
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public virtual System.Collections.IEnumerator GetEnumerator()
            {
                return this.Rows.GetEnumerator();
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public override System.Data.DataTable Clone()
            {
                AssignmentDataTable cln = ((AssignmentDataTable)(base.Clone()));
                cln.InitVars();
                return cln;
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override System.Data.DataTable CreateInstance()
            {
                return new AssignmentDataTable();
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            internal void InitVars()
            {
                this.columnPayload = base.Columns["Payload"];
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            private void InitClass()
            {
                this.columnPayload = new System.Data.DataColumn("Payload", typeof(byte[]), null, System.Data.MappingType.Element);
                base.Columns.Add(this.columnPayload);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentRow NewAssignmentRow()
            {
                return ((AssignmentRow)(this.NewRow()));
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override System.Data.DataRow NewRowFromBuilder(System.Data.DataRowBuilder builder)
            {
                return new AssignmentRow(builder);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override System.Type GetRowType()
            {
                return typeof(AssignmentRow);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override void OnRowChanged(System.Data.DataRowChangeEventArgs e)
            {
                base.OnRowChanged(e);
                if ((this.AssignmentRowChanged != null))
                {
                    this.AssignmentRowChanged(this, new AssignmentRowChangeEvent(((AssignmentRow)(e.Row)), e.Action));
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override void OnRowChanging(System.Data.DataRowChangeEventArgs e)
            {
                base.OnRowChanging(e);
                if ((this.AssignmentRowChanging != null))
                {
                    this.AssignmentRowChanging(this, new AssignmentRowChangeEvent(((AssignmentRow)(e.Row)), e.Action));
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override void OnRowDeleted(System.Data.DataRowChangeEventArgs e)
            {
                base.OnRowDeleted(e);
                if ((this.AssignmentRowDeleted != null))
                {
                    this.AssignmentRowDeleted(this, new AssignmentRowChangeEvent(((AssignmentRow)(e.Row)), e.Action));
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            protected override void OnRowDeleting(System.Data.DataRowChangeEventArgs e)
            {
                base.OnRowDeleting(e);
                if ((this.AssignmentRowDeleting != null))
                {
                    this.AssignmentRowDeleting(this, new AssignmentRowChangeEvent(((AssignmentRow)(e.Row)), e.Action));
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public void RemoveAssignmentRow(AssignmentRow row)
            {
                this.Rows.Remove(row);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public static System.Xml.Schema.XmlSchemaComplexType GetTypedTableSchema(System.Xml.Schema.XmlSchemaSet xs)
            {
                System.Xml.Schema.XmlSchemaComplexType type = new System.Xml.Schema.XmlSchemaComplexType();
                System.Xml.Schema.XmlSchemaSequence sequence = new System.Xml.Schema.XmlSchemaSequence();
                Assignments ds = new Assignments();
                xs.Add(ds.GetSchemaSerializable());
                System.Xml.Schema.XmlSchemaAny any1 = new System.Xml.Schema.XmlSchemaAny();
                any1.Namespace = "http://www.w3.org/2001/XMLSchema";
                any1.MinOccurs = new decimal(0);
                any1.MaxOccurs = decimal.MaxValue;
                any1.ProcessContents = System.Xml.Schema.XmlSchemaContentProcessing.Lax;
                sequence.Items.Add(any1);
                System.Xml.Schema.XmlSchemaAny any2 = new System.Xml.Schema.XmlSchemaAny();
                any2.Namespace = "urn:schemas-microsoft-com:xml-diffgram-v1";
                any2.MinOccurs = new decimal(1);
                any2.ProcessContents = System.Xml.Schema.XmlSchemaContentProcessing.Lax;
                sequence.Items.Add(any2);
                System.Xml.Schema.XmlSchemaAttribute attribute1 = new System.Xml.Schema.XmlSchemaAttribute();
                attribute1.Name = "namespace";
                attribute1.FixedValue = ds.Namespace;
                type.Attributes.Add(attribute1);
                System.Xml.Schema.XmlSchemaAttribute attribute2 = new System.Xml.Schema.XmlSchemaAttribute();
                attribute2.Name = "tableTypeName";
                attribute2.FixedValue = "AssignmentDataTable";
                type.Attributes.Add(attribute2);
                type.Particle = sequence;
                return type;
            }
        }

        [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Data.Design.TypedDataSetGenerator", "2.0.0.0")]
        public partial class AssignmentRow : System.Data.DataRow
        {

            private AssignmentDataTable tableAssignment;

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            internal AssignmentRow(System.Data.DataRowBuilder rb)
                :
                    base(rb)
            {
                this.tableAssignment = ((AssignmentDataTable)(this.Table));
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public byte[] Payload
            {
                get
                {
                    try
                    {
                        return ((byte[])(this[this.tableAssignment.PayloadColumn]));
                    }
                    catch (System.InvalidCastException e)
                    {
                        throw new System.Data.StrongTypingException("The value for column \'Payload\' in table \'Assignment\' is DBNull.", e);
                    }
                }
                set
                {
                    this[this.tableAssignment.PayloadColumn] = value;
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public bool IsPayloadNull()
            {
                return this.IsNull(this.tableAssignment.PayloadColumn);
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public void SetPayloadNull()
            {
                this[this.tableAssignment.PayloadColumn] = System.Convert.DBNull;
            }
        }

        [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Data.Design.TypedDataSetGenerator", "2.0.0.0")]
        public class AssignmentRowChangeEvent : System.EventArgs
        {

            private AssignmentRow eventRow;

            private System.Data.DataRowAction eventAction;

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentRowChangeEvent(AssignmentRow row, System.Data.DataRowAction action)
            {
                this.eventRow = row;
                this.eventAction = action;
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public AssignmentRow Row
            {
                get
                {
                    return this.eventRow;
                }
            }

            [System.Diagnostics.DebuggerNonUserCodeAttribute()]
            public System.Data.DataRowAction Action
            {
                get
                {
                    return this.eventAction;
                }
            }
        }
    }
}

Save the following file as test.xml:

<?xml version="1.0" ?>
<Assignment xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <Assignment>
    <Payload>54686973206973206A7573742061207465737421</Payload>
  </Assignment>
</Assignment>

Save the following file as test.xsd(the project doesn't use it, just for your reference):

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema id="Assignment" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <xs:element name="Assignments" msdata:IsDataSet="true" msdata:Locale="">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="Assignment">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="Payload" type="xs:hexBinary" minOccurs="0" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>