I have an XML document and style sheet like below. What I want to do is to filter the xml so that if the "Expire" date is less than the current date it is not processed by the style sheet and thus not included in the HTML produced. How do I do this?

<?xml version="1.0" standalone="yes"?>
<PICNews>
  <xsd:schema id="VFPData" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
    <xsd:element name="VFPData" msdata:IsDataSet="true">
      <xsd:complexType>
        <xsd:choice maxOccurs="unbounded">
          <xsd:element name="news" minOccurs="0" maxOccurs="unbounded">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="Date" type="xsd:date"/>
                <xsd:element name="Expires" type="xsd:date"/>
                <xsd:element name="Author">
                  <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                    </xsd:restriction>
                  </xsd:simpleType>
                </xsd:element>
                <xsd:element name="Type">
                  <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                    </xsd:restriction>
                  </xsd:simpleType>
                </xsd:element>
                <xsd:element name="Text">
                  <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                    </xsd:restriction>
                  </xsd:simpleType>
                </xsd:element>
              </xsd:sequence>
            </xsd:complexType>
          </xsd:element>
        </xsd:choice>
        <xsd:anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax"/>
      </xsd:complexType>
    </xsd:element>
  </xsd:schema>

  <news>
    <Date>6/21/2007</Date>
    <Expires>6/30/2007</Expires>
    <Author>Dan Jurden</Author>
    <Type>Memo</Type>
    <Text>This is a memo.</Text>
  </news>
  <news>
    <Date>6/21/2007</Date>
    <Expires>6/30/2007</Expires>
    <Author>Dan Jurden</Author>
    <Type>News</Type>
    <Text>This is some news.</Text>
  </news>
  <news>
    <Date>6/22/2007</Date>
    <Expires>6/23/2007</Expires>
    <Author>Dan Jurden</Author>
    <Type>Alert</Type>
    <Text>This is an alert.</Text>
  </news>
</PICNews>

<?xml version="1.0"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ddwrt2="urn:frontpage:internal">
  <xsl:template match="/">
    <h2>PIC Information</h2>
    <table width="100%">
      <xsl:for-each select="PICNews/news">
      <xsl:sort select="Date" order="descending" />
      <tr>
        <xsl:if test="Type = 'Memo'">
          <td width="32px"><img src="images/memo.jpg" width="32px" /></td>
        </xsl:if>
        <xsl:if test="Type = 'News'">
          <td width="32px"><img src="images/news.jpg" width="32px" /></td>
        <xsl:if>
        <xsl:if test="Type = 'Alert'">
          <td width="32px"><img src="images/alert.jpg" width="32px" /></td>
        </xsl:if>
        <td>Date: <xsl:value-of select="Date"/></td>
      </tr>
      <tr>
        <td colspan="2"><span class="news-text"><xsl:value-of disable-output-escaping="yes" select="Text" /></span></td>
      </tr>
      <tr>
        <td colspan="2"><br/></td>
      </tr>
    </xsl:for-each>
    </table>
  </xsl:template>
</xsl:stylesheet>