[xsl] Setting a foreign attribute

["Mark Wilson" <mark@xxxxxxxxxxxx>]

Hi all,
FOP does not like this fragment and calls <xsl:use-attribute-sets> a foreign 
attribute.

                   <fo:block>
                        <xsl:choose>
                               <xsl:when test="parent::Item">
                                   <xsl:attribute name=" 
xsl:use-attribute-sets">article0</xsl:attribute>
                               </xsl:when>
                               <xsl:when test="parent::Level1">
                                   <xsl:attribute name=" 
xsl:use-attribute-sets">article1</xsl:attribute>
                               </xsl:when>
                               <xsl:when test="parent::Level2">
                                   <xsl:attribute name=" 
xsl:use-attribute-sets">article2</xsl:attribute>
                               </xsl:when>
                               <xsl:when test="parent::Level3">
                                   <xsl:attribute name=" 
xsl:use-attribute-sets">article3</xsl:attribute>
                               </xsl:when>
                           </xsl:choose>

                                   .....
                       </fo:block>

Is there a way to set <xsl:attribute-sets> similar to my unacceptable 
construction, or do I have to create all six attributes for each <xsl:when>?

Thanks,
Mark