an expression / a parameter within <xsl:include href='$xxx'/> not allowed?

Hi,

 

until now I used 

 

      <xsl:include href="../temp/titlepageFO.xsl"/>

 

and it worked fine. As I generalize my scripts from now
on I have to use an expression 

to build the href value. 

 

My understanding
of the XLS specification is, that expressions are allowed within an href attribute.

 

I tried

 

      <xsl:include href="$baseDir/temp/titlepageFO.xsl"/>

      <xsl:include href="{$baseDir/temp/titlepageFO.xsl}"/>

      <xsl:include href="{$baseDir}/temp/titlepageFO.xsl"/>

 

but none of these variants works nor with XALAN neither
with SAXON. (The $baseDir parameter works surely,
because it delivers the right value in another expression).

 

Has anybody an
idea?

 

Best Regards

 

Joerg Moebius