passing an xml fragment to xslt

[Gert-Jan van de Streek]

I want to pass an xml fragment to an xslt. I have the following code  
where the queue holds xml messages

        from("activemq:example.A")
                .setHeader("agent.id", new XPathExpression("/"))
                .process(new ReadLocalFile())
                .to("xslt:transform.xsl")


The xslt looks like:

    ...
    <xsl:param name="agent.xml"/>

        <xsl:template match="/">
                <xsl:value-of select="$agent.xml/agent/id" />


I would expect the xml fragment to be available as a nodeset in the  
xsl, but I get the following exception:

javax.xml.transform.TransformerException: java.lang.RuntimeException:  
Invalid conversion from  
'com.sun.org.apache.xml.internal.dtm.ref.DTMNodeList' to 'node-set'.
	at  
com 
.sun 
.org 
.apache 
.xalan 
.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:670)
	at  
com 
.sun 
.org 
.apache 
.xalan 
.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:300)
	at org.apache.camel.builder.xml.XsltBuilder.process(XsltBuilder.java: 
83)
        ...

Any ideas on how to solve this?