[xsl] xsl:number on attribute nodes..

[Jack Matheson <jack@xxxxxxxxxxxxxx>]

Can anyone tell me the correct action to take when xsl:number is  
executed and the current node is an attribute?

I have a quick example:

<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";  
version="1.0">
  <xsl:template match="/">
    <xsl:apply-templates select="//@* | //*"/>
  </xsl:template>

  <xsl:template match="@* | *">
    <xsl:number count="@* | *"/>
  </xsl:template>
</xsl:stylesheet>

Saxon 6.5.4 gives me the following error:
Error at xsl:number on line 8 of file:test.xsl:
  Attribute nodes cannot be numbered
Transformation failed: Run-time errors were reported

Xalan 2.7 produces the following output:
<?xml version="1.0" encoding="UTF-8"?>11

Is this an "up-to-the-implementer" case?

Any help would be appreciated!

-Jack