Well, I downloaded a free trial of 3DS Max and gave it a shot myself, all I did was import, select and delete the head and hood geometry, and export it, the model looks perfect but I seem to have lost all of the animations in the process. MDLedit did give me an error about not finding the binary supermodel, whatever that means, so I'm assuming that's where the animations were lost?
Note: I do not intend to release this, only use it for my own playthrough. The way I'm using the Jaesa head wouldn't be compatible with the player version of that mod anyway I don't think.