IPP printing in FC6?

[Jack Howarth]

   I have had trouble setting up IPP printing
to a Xerox Phaser 6250 printer under both MacOS X
and Fedora Core 6. The problem is that this printer
resides on the other side of a firewall in a
different subnet. On MacOS X this is a problem
because their default is only to allow IPP within
a subnet and must be worked around with the
Advanced settings.
   Under Fedora Core 6, I have similar problems
which I have only been able to work around
by using the CUPS web browser interface to
setup the printer. The printer requires the
use of a Device URI of the form...

http://phaser6250.foo.bar:631/ipp/port1

for IPP printing using http or

ipp://phaser6250.foo.bar:631/ipp/port1

for IPP printing using ipp.

Is there any way to obtain those settings
using the printer setup tool in FC6 without
resorting directly to the CUPS web browser
interface? Thanks in advance for any 
clarifications.
              Jack