[xsl] FW: construct node-set from list of strings

["Rick Roen" <Rick@xxxxxxxxxxxxxxxxxx>]

Using Saxon 8.7.1 XSLT 2.0

I have an xml document which can be any one of various types of sales
document, packing list, invoice etc.

Id like to create various variables for node sets as variables at the top
of the xslt.

I would like to do something like this:

	<xsl:variable name=my-nodeset>
           	 <xsl:if test=test1><xsl:value-of select=invoicenum,
purchaseordernum, terms, invoice-date/></xsl:if>
            <xsl:if test=test2><xsl:value-of select=ordernum,
purchaseordernum, terms, ship-date/></xsl:if>
	</xsl:variable>

Then, later in the document I want to use this variable like this:

	<xsl:template select=$my-nodeset />

I have tried xs:QName(invoicenum), xs:QName(purchaseordernum) but that
doesnt do anything to help.

How do I get a list of QNames into my variable so I can use it in my select?

Thanks,

Rick