Windows XP pro vs Okidata 390 Turbo (Custom forms)

I hae seen this problem around, but have yet to find a solution. Let me
descibe the situation. In our accounting office, we use a new Okidata 390
Turbo to print checks. The form for the checks is 8.5 x 7. It was simple in
Win98, but after upgrading to Win XP pro....it will not work. I have followed
the instructions on creating a custom form...it is in the "server
properties", but you cannot select it under the printer properties...the
printer is networked (runs on a Win NT box). Okidata says it's Microsoft,
Microsoft says it's Okidata.......HELP!

Thanks,