db5 xl:href in bibliographies

Is this supposed to generate links in any of the output formats yet?
Maybe I did it wrong. I put one of my biblioentries below for
reference. In the output (pdf, html, and xhtml), I don't see any
links. If this needs to be added to the stylesheet, could someone
please tell me the name of the template that handles xl:href?

	<biblioentry xml:id="MHEM">
		<abbrev xml:id="MHEM_abbrev">MHEM</abbrev>
		<editor>
			<personname>
				<firstname>Michiel</firstname>
				<surname>Hazewinkel</surname>
			</personname>
		</editor>
		<title xl:href="http://eom.springer.de/">Encyclopaedia of
			Mathematics
		</title>
		<biblioid class="isbn">1-4020-0609-8</biblioid>
		<copyright>
			<year>2002</year>
		</copyright>
		<publisher>
			<publishername xl:href="http://springer.de">
				Springer-Verlag
			</publishername>
			<address><city>Berlin</city> <city>Heidelberg</city> <city>New
York</city></address>
		</publisher>
	</biblioentry>

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http://chris.chiasson.name/