MSXML4, key() across node-set

As far as I can tell, when using a key() with the MSXML4 extention
node-set(),
the call to key('key-name', val)[1] does not always return the same node for
a constant val.

I have this stylesheet:

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt">

<xsl:variable name="set"
select="msxsl:node-set(document(/files/node/@path))"/>
<xsl:key name="k-id" match="person" use="@id" />

<xsl:template name="distinct">
        <xsl:for-each select="$set/doc/person[@id='4']">
            <info self-id="{generate-id(.)}"
index-id="{generate-id(key('k-id',@id)[1])}">
                <self>
                    <xsl:copy-of select="."/>
                </self>
                <index>
                    <xsl:copy-of select="key('k-id',@id)[1]" />
                </index>
            </info>
        </xsl:for-each>
</xsl:template>

<xsl:template match="/">
<test>
<xsl:call-template name="distinct" />
</test>
</xsl:template>
</xsl:stylesheet>

And two input files:

-------------------------------------------
input1.xml
<?xml version="1.0" encoding="utf-8" ?>
 <doc>
        <person name="onePerson" id="4" />
</doc>
-------------------------------------------
input2.xml
<?xml version="1.0" encoding="utf-8" ?>
 <doc>
        <person name="otherPerson" id="4" />
</doc>
-----------------------------------------------
When I run my stilesheet I get:

 <?xml version="1.0" encoding="UTF-16" ?>
- <test xmlns:msxsl="urn:schemas-microsoft-com:xslt">
- <info self-id="IDAUQ2N" index-id="IDAUQ2N">
-     <self>
          <person name="onePerson" id="4" />
      </self>
-     <index>
          <person name="onePerson" id="4" />
      </index>
      </info>
-         <info self-id="IDAIY2N" index-id="IDAIY2N">
-     <self>
          <person name="otherPerson" id="4" />
      </self>
-     <index>
          <person name="otherPerson" id="4" />
      </index>
      </info>
  </test>

It looks like there is a seperate key for each tree-fragment in the
node-set.
Did I miss something, or is this a known problem?

-alex




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