Ok, thanks. I think this list of functions should be somewhere on the wiki though.
Since the workaround I suggested doesn't seem to be possible, I thought about another :
Still with my Martial Artist and my unarmed ability example, what if I added a new item that would be given to the player through a custom quest or bought from a "Martial Artist Master"?
As long as the player keeps this item in his inventory, his unarmed damaged would be boosted. This item could stack and boost his damage even more (depending on the number of stacked items) and behave kind of like a combat ability (+5% unarmed damage per item stacked for instance).
Would something like that be doable?
Side questions :
5) Is there a way to know when a character levels up?
6) Is there a way to know when a player assigns a unused points to a combat ability?