I found the following to work pretty well.

 <xsl:template match="idx/item">
 <fo:block 
   start-indent="0.5in" 
   end-indent="0.5in" 
   font-size="{$base-font-spec}"
   text-align-last="justify">
   <xsl:apply-templates/>
 <fo:leader leader-pattern="dots"/><fo:basic-link
 internal-destination="{@idref}"> <fo:page-number-citation color="blue"
ref-id="{@idref}"/></fo:basic-link>
</fo:block>
 </xsl:template>

HTH DaveP

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