Can't print collated copies

[Billy DeVincentis]

I have an HL-4200cn color laser and an HP laserjet 2840. When I attempt to print multiple copies of a pdf guide (choosing the collate tab in kprint dialog box), the copies don't collate. I am using cups-1.3.9 on Gentoo with a kde desktop. The hp 2840 uses the lasejet 2800 series postscript driver and the Brother uses the plain postscript driver (but I have also tried the hl-4000cn driver and also a ppd file specifically  for the hl-4200cn under Mac). Can anyone give me some clues on fixing this? I need to be able to print 20-30 copies of this 25 page guide daily. Thanks. BTW, it seems to print collated under Windows XP ( but I hate to have to start my XP box all the time)