HP: problems with tray selection?

[sheldonw at infospace.com]

I'm having problems getting CUPS (1.1.21) to print to the correct paper tray on either of two HP printers (LaserJet 4101 and LaserJEt 8100. It insists on printing to tray #1, which forces me to go to the printer and manually select another tray. I am configuring CUPS through the SUSE Printer configuration tool.
I've tried setting 'Media Source' to 'Auto' and 'Tray 3'.
I've tried setting 'Media Size' to various values.
No success.
Anyone know how to get one of these things to just find the right tray? It works perfectly from my windows box. I don't have the liberty of reconfiguring the printers themselves to my liking.