HP DesignJet 5000PS - overriding internal rip?

[Jon Beebe]

I have a 60" HP DesignJet 5000PS.  When I print via cups it uses the internal RIP, which is slow and sometimes error-prone.  I would like to have CUPS do the ripping of the files and override the printer's internal rip.  I know this can be done because I run an Onyx rip that overrides the internal HP rip.  But can I do this via CUPS, and if so, how?

I am currently running cups 1.3.6 on OS X Leopard.

Any input would be greatly appreciated!  Thanks.

Jon Beebe