OT - AT&ATX PSU compatibility

Is it possible to run an ATX board from an AT power supply? I checked the pin setup on both, the only thing that's missing is the 3.3v, which I assume is for communication between the board and PSU which shouldn't be neccessary, since I would be switching the PSU on and off directly. Thanks Hans == Find businesses and have your business found: http://www.brabys.com