CData tags are usually swallowed up by an XSLT transformation. If they are important to your output document, you can use the following method to include CData tags.
<xsl:text disable-output-escaping="yes"><![CDATA[</xsl:text> <!-- text between CData tags here --> <xsl:text disable-output-escaping="yes">]]></xsl:text>
The output will look like:
<![CDATA[ ]]>