Adding media type to LJ 4350dtn

I have searched, scratched my head, searched again. But I simply cannot
find out how to add a media type to an HP LaserJet 4350dtn (obviously
will be the same as several other models - but I wanted to be specific
just in case).

The users load two different sorts of preprinted form into trays 2 and 3
respectively. They then print - and have to choose between "Preprinted"
and "Cardstock". Perhaps not suprisingly they would rather the media
were called "Intro Form" and "Certificates" (or whatever would help them
to remember).

The printer is on a network with a Windows 2003 domain controller. The
printer was installed on the server then "added" to each PC as needed.

They have PCL 5e, PCL 6 and PS drivers available. And the printer has
had the most recent firmware installed. (No - I can't remember the exact
identitiies but they were downloaded within the past couple of weeks).

--
Rod