Roxen / XSLT: Import the XML?

[Christopher Howard]

I just started learning XSLT, and I figured out that I can use this 
through the xsltransform tag:

<nocache>
<xsltransform xsl="/arsc/scratch/test.xsl">
...xml goes here...
</xsltransform>
</nocache>
What do I do if I don't want to put the XML there but instead load it in 
from another file? I tried an SSI include tag, but that doesn't seem to 
work here:

<nocache>
<xsltransform xsl="/arsc/scratch/test.xsl">
<!--#include virtual="test.xml" -->
</xsltransform>
</nocache>

This gives the transform error "Root element missing", which I'm 
guessing means the include isn't being processed.
<<attachment: cmhoward2.vcf>>