ZBrushCentral

(Maya 2010) A question about blend shapes and normal maps

hi. this is actualy a bit of a maya question but I thought I’d try posting it here. I hope someone can help me with some info on this. I just started playing with facial blend shapes and I was wonering if it’s possible to have different normal maps for each blend shape (ie if you have a nutral face and then blend it into a srewed up angry face, would it be possible to blend between two different normal maps)
I hope this makes sense.

I’m currently using maya 2010 and renering with mental ray.

even if I’m barking up the wrong tree with my aproach to how this prosses may work i’d really appreciate being pointed in the right direction.
cheers