Remote printer IPP authentication problem

[Michael ORourke]

Recently I added a couple of Ubuntu 7.04 workstations onto a small network with a big PRINTER.  The printer is really an office copier with additional capabilities, such as... network printing, scanning, and faxing.  It is a Konica Minolta bizhub C550, which has been configured from the leasing company with authentication enabled.  The Windows clients can print to the C550 without any problems.  So network printing is functioning correctly.  I was able to add the device as an IPP printer in CUPS (forgot which vesion, but it's the one that comes stock with Ubuntu 7.04).  When I send a print job to the printer, it goes into the queue and then the C550 deletes the print job and gives an authentication error in the C550 logs.  I have the username/password pair, but I'm not sure where to configure that on the CUPS side.  Any suggestions on where to start?