xerox 3500dn printer installation problem.

Hi,

I have a Xerox 3500 duplex printing network printer and I downloaded the CUPS driver from Xerox and installed it. However the xrx3500.ppd file has default option for duplex as none and in the menu (Printing menu), I am not able to choose a duplex option. I tried editing the xrx3500.ppd file but to no resolution yet.

Also the default resolution is 600dpi and I would like it to be 1200dpi.

Any ideas on how to set these two things up?

Thanks.