Using URL params as xml tag attributes

I would like to use a URL parameter in my Cocoon-XSLT as an attribute in a
XML tag.
(http://www.yourdomain.com:8080/cocoon/vc/Hello.xml?djUser.id=1&djUser.first
Name=Mike)

You will notice that I use the djUser.firstName successfully to mention the
person's name, but can not use djUser.id as a value in a XML tag attribute
(VoiceXML var tag.)

It returns <var expr="" name="djUser.id" /> I need it to return <var
expr="1" name="djUser.id" />  So, how do I fix this?


Code:

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:param name="djUser.id"/>
<xsl:param name="djUser.firstName"/>


<xsl:template match="user">

<vxml version="2.0">

    <var name="djUser.id" expr="{(_at_)djUser(_dot_)id}"/>

    <form id="getEntry">
        <block name="welcome">

              <prompt>
                Hello, <xsl:value-of
select="$djUser.firstName"/><xsl:apply-templates/>, what would you like to
do today?
              </prompt>