Setting Sort From Variable

Hi Again,

I have a looping for-each and need to sort the list. There are 2 values that I would like to sort by and both show the same HTML output so it would be good if I could just set the 

<xsl:sort select={$orderBy}" order="ascending" />

where orderBy variable is set to "@forename" or "@surname".

This does not work. I have also tried within the for-each

<xsl:choose>
  <xsl:when test="$filterOrderBy = 'forename'">
    <xsl:sort select="@forename" order="ascending" />
  </xsl:when>
  <xsl:otherwise>
    <xsl:sort select="@surname" order="ascending" />
  </xsl:otherwise>									
</xsl:choose>

But sort must be a child of for-each I think.

Any ideas?


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