Table:table-cell spanning several columns (xslt)

Is it possible to make specific cells span several columns in xslt import filter for calc?

By the way if anyone is aware of good docs on openoffice xslt filter features please drop a link!

I would imagine this is possible via the table:number-columns-spanned="N" attribute, where N is an integer greater than 1. Having a look at the XSL Excel to Calc filter that comes with LO v4.0.3.3 (/opt/libreoffice4.0/share/xslt/share/import/spreadsheetml/spreadsheetml2ooo.xsl) I can see this:

<xsl:if test="@ss:MergeAcross or @ss:MergeDown">
		<xsl:when test="@ss:MergeAcross">
			<xsl:attribute name="table:number-columns-spanned">
				<xsl:value-of select="@ss:MergeAcross + 1"/>
			<xsl:attribute name="table:number-columns-spanned">1</xsl:attribute>

That would seem a fair translation of the MergeAcross element (MOX/OOXML) into the number-columns-spanned attribute (ODF).