GNOME Printing problems

Hi, I've set up a machine with SUSE Linux 10.1. I've also set up an additional Linux machine running CUPS configured with and sharing an HP LaserJet 4050 printer with 4 trays, A4 as default paper size, and using the PostScript driver. Once logged into SUSE Linux 10.1 I can see the exported printers but the print dialog from any GNOME application will show US Letter as the default paper size and won't allow me to change the tray since the source media tray dropdown appears grayed out. What is extremely curious is that OpenOffice.org, KDE applications, KPrinter and Mac OS X allow me to choose to print to any of the 4 trays and A4 appears as the default paper size. Any idea on what is happing here? Thank you very much.