Forced duplex printing using Windows 2003 Server

We have many HP Laserjet printers with duplexers. They are all used via a
Windows 2003 Print Server. We have been asked to change the printer
configuration so that all printing is duplex printing. We can configure the
default printing to be duplex, but management wants to mandate all printing
be done using duplex printing and single side printing is not available under
any circumstance. We have contacted HP, BUT they indicate that they do not
support any network printing from servers. WHAT? I ended up talking to one
of there managers and they indicated because of liability issues they can't
and won't help trying to make this modifications. Any suggestions
appreciated.