More trays?

Our office got a new HP LaserJet 2420dn printer yesterday to replace an old LJ6 (that was woefully inadequate for office use).

Installation of the printer drives went fine (as long as you call a 67% success rate in the first round fine - now we are at 100%)

Notray Today the additional 500-page tray arrived and was installed. On Windows it was a snap to tell the printer driver, that there is another tray to be served from. On OS X (the Tiger variant) - no such luck. I can print no problem, but the drivers insists on only having 2 trays. And the place where I can select memory and duplex option has no little checkbox for selecting the additional tray. What is the wisdom out there for these kind of problems? Google is no help. Can it be, that Windows is better than Mac OS X?