Welcome to SimV,
Use the number keys on the keyboard, not the numpad.
Quoted from the FSX Learning Center
Quote: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.
Press SHIFT+P again to stop moving back.
It takes approx 1/2 plane length for turns to begin. Turns continue for 90*, then straight back.
There are 2 more keys that can be used while in Pushback-
3-will pause the pushback. Continue by pressing 1, 2, or 4
4-will end the turn and continue straight back.
Do not press any other keys while in pushback as the sim may no longer respond to the number keys.
With a little practice you can parellel park a 747..

Dave
At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation. Igor Sikorsky
I intend to live forever....so far, so good. Steven Wright
You know....you can just rip up a to-do list.