I get it to snap up, but it returns to off and will not stay engaged.  Huummmmmm?????
Mine works fine. It wont stay up if there isn't any External Power (of course), but if I do have EP the switch goes up and stays up.

Maybe this isn't so important: I have started a thread about it; Pushback and turns aren't possible? As I say in my new thread I had installed Rob berengredts' gauge to be able to do this: I like to start my flights as realistically as possible from the gate...But turns aren't possible.

Have you tried using the Ship+P+1 (for left) or Shift+P+2 (for right)? The following is from FSX help regarding pushback.

Pushback

Most of the time, the aircraft parked at a gate in Flight Simulator will be the larger planes, like the Boeing 737, Boeing 777, and the Boeing 747. These planes must be pushed back from the gate before they can taxi to the runway. In the real world, this task is accomplished by a "tug," a small tractor designed for the job. When you're parked at a gate in Flight Simulator, you'll need to have your aircraft pushed back before you can request a taxi clearance.

To get a pushback

  1. Press SHIFT+P to push straight back.
     - or -
     Press SHIFT+P and then press 1 to turn the tail of the aircraft to the left as it pushes back.
     - or -
     Press SHIFT+P and then press 2 to turn the tail of the aircraft to the right as it pushes back.
  2. Press SHIFT+P again to stop moving back.

After the pushback, the ATC menu includes a Request Taxi option.

I do this on all my Captain Sim aircraft and it works fine for me.

Mark