Using keys to filter nodesets

I am trying to use a key to filter a nodeset. The individual elements work,
but when I put them all together the nodeset does not get filtered. What am
I doing wrong? - Maria


<xsl:key name="MappingKey"
match="/PresentationData/PageSpecific/SubscriptionList/Subscription/WDBiller
ID" use="../SubscriptionID"/>


<xsl:template match="//Biller[WDBillerID = key('MappingKey',
/PresentationData/PageSpecific/SubscriptionList/Subscription/SubscriptionID[
1])]">
        <option>
                <xsl:attribute name="value"><xsl:value-of
select="MappedBillerID"/></xsl:attribute>
                <xsl:value-of select="MappedBillerName"/>
        </option>
</xsl:template>


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list