oops, sorry, I was in the Blizz-ABS swing ^_^'
Try this:
Input.trigger?(Input::KEY_CONSTANT)
where KEY_CONSTANT can be any RMXP key. The available keys are:
DOWN LEFT RIGHT UP: The directions
A B C X Y Z L R: C is basically the confirm key and B is the cancel key. A is the shift key.
SHIFT CTRL ALT
F5 F6 F7 F8 F9
Press F1 while running a game and you can check what keyboard keys are mapped to these controls.