Putting a nodeset in a variable

Hello,

is it possible to put a nodeset in a variable. 
What I try to do is the following. I have an xml file which I want to group.
This resulting tree I want to put in a variable so I can use it later on.

E.g.
	<traps>
		<trap id="5"/>
		<trap id="6"/>
		<trap id="2"/>
		<trap id="5"/>
	</traps>

	<xsl:variable name="distinctValues">
		<traps>
		<xsl:for-each select="traps/trap">
			<xsl:sort select="./@id"/>
			<xsl:copy-of select="."/>
		</xsl:for-each>
		</traps>
	</xsl:variable>

	<xsl:template match="/">
		<xsl:for-each select="$distinctValues/trap">
			<xsl:value-of select="@id"/>
		</xsl:for-each>
	</xsl:template>

When I try to do this I get following error:
	Expression must evaluate to a node-set.

Can somebody give me a hint if this is possible ?

Kind regards,
Ismaël




 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list