passing a node name as a param and then using it

I want to be able to pass a node name into a named
template as a param and
then operate on it.  When I try to use the node name
param in the template, 
it gets interpreted as a string and not an actual
node.   i.e.
 
The snipett:
<xsl:variable name="x" select="choice"/>
<fo:block>a: <xsl:value-of
select="choice[1]"/></fo:block>
<fo:block>b: <xsl:value-of
select="concat($x,'[1]')"/></fo:block>
 
Will generate:
a: {the actual xml data in the 1st choice node}
b: choice[1]
 
How do I get this to work as intended?
 
Thanks,  Mike


                
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