I don't see the point of mapping buttons to B-K and A-B but I can understand A-K.
I'd feel dead cheap using one button for B-K, A-B, then again maybe I should try it out. Only problem is I'd have to have no button for a taunt or a CF :P
i was having a hard time hitting ivy's 6bA+B 100% so i mapped a+b and problem solved. likewise, I mapped B+K to do yoshi's a:B+K