Xalan Extension Parameter

I'm trying to pass an <xsl:param> into an extension function using Xalan
2.3.1. 

If I do something like:
    <xsl:template name="DocletContentBody">
        <xsl:param name="docletTemplate"/>

        <dynamicTemplate:dynamicCallTemplate name="$docletTemplate">
            <xsl:call-template name="doesntMatter">
            </xsl:call-template>
        </dynamicTemplate:dynamicCallTemplate>
    </xsl:template>

where dynamicTemplate is my extension function, the value of the name
parameter evaluates to "$docletTemplate" rather than the value of the
parameter.

Any ideas?

Paul.

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