If I remember right, MK is mapped like this:
1 2
3
4 5
So you have to remap the keys for all of the MK games.
I changed the button mapping as follows:
1: HP
2/5: Block
3: HK
4: LP
6: LK
So that either middle button (2/6) will block and the outside buttons are correct. Don't remember the actual keyboard keys represented though.