biblioref not yet supported?

Hello

I tried to link to a biblio-entry with <biblioref> as described in 'Docbook - 
TDG', but I always get this warning, when I try to render my document:

"biblioref encountered in para, but no template matches"

I'm using 'docbook-xsl-1.68.1/fo/docbook.xsl', xsltproc and FOP 0.20.5.

I ran a fulltext search over all files in the stylesheet distribution but 
'biblioref' was found nowhere. So, is this element just not yet supported by the 
stylesheets or is something wrong with my setup?


Greetings, Thomas