Following up on the suggestions, and the code, I have constructed an XSLT that sends the XPath for the context node through a form POST. I'm picking up the form parameter following the FAQ for form parameters. Now I have a new problem: When I try to select based on the param, sablotron borks that it needs a node set, not a string. How do I turn the string ($the_param) into a node-set so I can use it like this

<xsl:param name="AddOne">default</xsl:param>
<!--sablotron or Axkit replaces that with the proper parameter from the http post-->
[...]
<xsl:apply-templates select="$the_param"/> <!--borks-->

?

simon