xsl:sort question

I'm trying to leverage parameter passing in the latest XT (19990822) with
sorting.  Here is my XSL.

  <xsl:variable name="sortcolumn">Site</xsl:variable>
  <xsl:variable name="sortdirection">descending</xsl:variable>

   sort=<xsl:value-of select="$sortcolumn"/>
    <xsl:apply-templates select="somedata">
      <xsl:sort select="$sortcolumn" order="descending"/>
    </xsl:apply-templates>

The problem is the data is not sorted.  If I change it to the following, it
works.
Notice the 'hard coded' value is the same as the value of the variable.  The
sort= statement
does output the proper value of the variable.

    <xsl:apply-templates select="xresource_utilization">
      <xsl:sort select="Site" order="descending"/>
    </xsl:apply-templates>

Any thoughts?
Thanks,
Larry Mason
i2 Technologies



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