problems with duplex printing

[Shamus Rask]

Ubuntu 10.04.2
CUPS 1.4.3
HP LaserJet 3055
CUPS+Gutenprint v5.2.5
driver: STP01419.ppd

The LaserJet3055 does not have a duplexer, but does have a tray by-pass to allow for manual duplexing. I have been unable to enable this from within CUPS. In CUPS, I have set my default options to two-sided long edge, but when I hit print, everything prints out single sided with no pause for flipping.

Does anyone have any insight on what I could do to fix this?