Your question doesn't follow. There is no connection between attaching a biped animation to your model in 3dsMax and collisions. Blitz only features sphere>something collisions, so your source object ( the one that's moving ) is always a sphere. Therefore, it makes no difference if you add collisions to a sphere, a pivot, a cylinder or a full animated biped characters.
So to clarify, are you having problems with the animated character or the collisions, or both?
So to clarify, are you having problems with the animated character or the collisions, or both?