if result-document filename='con.xml' -> java error?!

I'm getting a java error if a [xsl:result-document]'s filename is 'con.'+file extension (eg con.xml or con.txt)
.. but the ONLY word this appears to happen with - is 'con' ..

Error at xsl:text on line 6 of file:/C:/somedir/test.xsl
 java.io.FileNotFoundException: C:\somedir\con.xml (The system cannot find the
file specified)
Transformation failed: Run-time errors were reported.

--- .xsl example ---
<?xml version="1.0"?>
<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">

<xsl:template match="/">
<xsl:result-document href="file:///C:/somedir/con.xml">
 <xsl:text>&#10; Hello world!</xsl:text>
</xsl:result-document>
</xsl:template>

<xsl:template match="text()|@*"/>
</xsl:transform>
--- blank .xml -------
<blank/>
----------
java -jar C:\Saxon\saxon8.jar -w0 blank.xml test.xsl >log_test.xml

(this with Saxon 8.1.1 + java 1.4.2)
?