But the dataset is a parameter on my WebService function. The function doesn't even get called properly, I get the SOAP error and the .NET debugger doesn't even fire :(

Here is my function

[WebMethod]
public string AnalyseMyData(DataSet dsCheckMe)
{
  //here we just need to return a string detailing the contents of the passed dataset
  string lcBlurb = string.Empty;

  //say how many tables
  lcBlurb += "DataSet Contains " + dsCheckMe.Tables.Count.ToString() + " Tables : " + Environment.NewLine;

  for (int i = 0; i < dsCheckMe.Tables.Count; i++)
  {
      lcBlurb += "\tTable " + Convert.ToString(i+1) + " is called " + dsCheckMe.Tables [i].TableName + " and has " + dsCheckMe.Tables[i].Rows.Count.ToString() + " Records" +  Environment.NewLine;
  }
  return lcBlurb;
}

Am I able to put constraints on this? Would I have to specify them from VFP?