'except' operator on atomic integer values

Hi all,
   I am trying to use the 'except' operator (to calculate set
difference) in a XSLT 2.0 stylesheet (using Saxon 9-b). My attempt is
below:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                         version="2.0">

 <xsl:output method="text" />

 <xsl:template match="">
   <xsl:variable name="seq1" select="(1,2,3)" />
   <xsl:variable name="seq2" select="(1,2)" />

   <xsl:value-of select="$seq1 except $seq2" />

 </xsl:template>

</xsl:stylesheet>

The sets (sequences) will contain atomic integer values (the values
are not nodes). The above stylesheet is giving error:
XPTY0004: Required item type of first operand of 'except' is node();
supplied value has item type xs:integer

Is it possible to cast atomic values like integers above to a suitable
node, so that except operator works on such data ?


-- 
Regards,
Mukul Gandhi