DocBook/XML --> [tgn]roff

I have a man page which I maintain in both HTML and groff formats.
I know that groff can output HTML, but I have some href links in the
HTML which I would rather keep.
So I want to switch to DocBook/XML for the page and produce both HTML
and roff out of it.
Have anyone done that?

PS.  docbook2man barfs with
nsgmls:<URL>http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd:112:17:E: "X20AC" is not a function name
nsgmls:<URL>http://www.oasis-open.org/docbook/xml/4.2/ent/iso-amsa.ent:8:19:E: "X21B6" is not a function name
nsgmls:<URL>http://www.oasis-open.org/docbook/xml/4.2/ent/iso-amsa.ent:9:19:E: "X21B7" is not a function name
nsgmls:<URL>http://www.oasis-open.org/docbook/xml/4.2/ent/iso-amsa.ent:10:17:E: "X21D3" is not a function name

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