How to write a well-formed XSLT file to transform a XML to Flatfile?

I'm failed to transform a XML to a flatfile.

Please show me what wrong have I made.

Thanks.

the XML file:

<?xml version='1.0' encoding='ISO-8859-1'?>
<TRANSFER>
<PATIENT>
<UPN>0165516</UPN>
</PATIENT>
</TRANSFER>

the XSLT file:

<?xml version='1.0' encoding='ISO-8859-1'?>
<xsl:stylesheet version='1.0'
xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
xmlns:fo='http://www.w3.org/1999/XSL/Format'>
<xslutput method="xml" encoding="ISO-8859-1" indent="yes"/>

<xsl:template match="TRANSFER/PATIENT/UPN">
<xsl:value-of-select="."/>
</xsl:template>

</xsl:stylesheet>

I think that it has to do with the fact that you are using single quotes (') instead of double quotes (") in your XML definition in the XSL file.

If you're targeting a flatfile your output method should probably be "text".