Millisecond Forums

My Question concerns the approach-avoidance task (AAT): http://www.millisecond.com/download/library/AAT/

In this task, participants react to certain images presented in portrait vs. landscape form by either pulling them towards themselves or pushing them away. Currently, the pushing vs. pulling can be done either via a joystick or computer mouse; however, I would like that pushing is done by pressing the forward arrow on the keyboard and pulling by pressing the backward arrow. Would anyone maybe know how to do this and how easy/difficult it is.

Thanks all! 

Dario