OKI printer questions

[Linda]

I am playing with an OKI B6500 printer. They provided me with their CD 
that has an old altered version of CUPS and a bunch of ppd files for 
Solaris, none of which  are for the B6500. Tony was kind enough to give 
me a link to a CUPS ppd file for the B6500. This ppd allows you to 
duplex and change orientation at the command line. However it does not 
have a way to indicate which tray to print with via the lpr -o media= 
command
Has anyone been able to indicate tray choice with a OKI B6500. If so 
what did you use for the driver file? I need to be able to tell it from 
the command line to print envelopes as the command is part of the 
program output.
                           Thanks
                            Linda