fo:table-cell with dynamical number of cells

Hi,


i'm using apache Fop to generate my Pdf so in my xsl to draw table i got :


<fo:table-row>  	     	   	        
  <fo:table-cell number-columns-spanned="$numberColumn" border="0.5pt solid black">
  <fo:block margin-top="2mm" text-align="left" font-weight="bold" font-size="9.0pt" font-family="Times">     			     
     <xsl:value-of select="label"/>
  </fo:block>
</fo:table-cell>    	     	   	        	     	   	     </fo:table-row>


while $numberColumn is a varible that i have defined  :


<xsl:variable name="numberColumn" select="count(/cv/Header)+1 "></xsl:variable>

when i print the value of $numberColumn it give em a result but assigning dynamicly "$numberColumn" to the attirute number-columns-spanned

doesn't work


and thanks for you help