Just a question for clarification. Does the printer have a built in postscript interpreter? I ask because many years ago I helped setup a company with Xerox Pantone printers and they had quite a sophisticated postscript interpreter.
If your printer can do postscript and you have a PPD file for it you should be able to add it to the PSPRINT Driver and run it over the network using the SLPR output port. I run all my Brother colour laser printers that way.