RSTA its not possible because each fighting style has its OWN moves but they are aquired to the same buttons.
Boss, I got a suggestion for you that I wanted to do a long time back, but im too much into Russell Mod so I'll give you the idea.
Action Node binder.
FIrst you chooce a button to bind (any button except for the menu buttons) and then it lets you chooce which move you want to bind into the button. The button can be reseted at any time.
This will allow players to mix styles in game with no knowledge of any kind of scripting/HxD