How can I control Player1_object's Max Speed in run time.

[RedeyeHunter]

I have been looking for a way to control player1_object's max speed in run time and can't seem to figure it out.

I am using the adventure module.

The behaviour I want to achieve is :

D-PAD UP = Increase Max speed by X
D-PAD Down = Decrease Max Speed by X (until 0 , negative would be nice for reverse but not needed)

Anybody got any ideas how I can do this?

Thanks.