I don't think JigLib dependent upon your renderer (in this case away3D). It also seems like the port is still in progress (http:// www.flashsandy.org/blog/jiglib-for-flash-as3-3d-physic-engine.html). I think it was also mentioned in an earlier post that the engine still had some bugs and wasn't the most accurate thing at the moment.
Not to say I could write the damn thing.
