To begin with, I'm modifying antgump for use in our build process.  The antgump-each.xsl stylesheet  contains the following snippets:
 
<snip>
<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:redirect="org.apache.xalan.xslt.extensions.Redirect"
                extension-element-prefixes="redirect">
</snip>
 
<snip>
<redirect:write file="{@name}-process.xml">
</snip>
 
When I run the build.xml file, the following transformation fails:
 
        <style in="${temp.dir}/sorted.xml"
               out="${temp.dir}/foo.xml"
               style="stylesheet/antgump-each.xsl" 
               destdir="${temp.dir}"/>
Specifically, it fails on the line with the <redirect:write> extension.  When I run the transformation from the command line (using org.apache.xalan.xslt.Process), it works fine.  I suspect the extension is causing the failure, but I'm unsure how to fix things.  I've tried specifying "xalan" as the processor, but that fails since I'm using Xalan-J 2.2.D10.  I'm also using Ant 1.3.  Does my hunch (that the extension's causing the failure) sound correct?  Anyone have an idea as to how to work around it?