How to edit a full body costume mesh?

Hi, this isn't really a problem but more like a question (pardon my grammar). I'm looking for a tutorial on how to edit full body meshes? I have Outdoor Retreat and I want to edit the Bear costume in the Full Body section but I want the head of the bear removed (that sounds really weird!) to reveal the sim's head. I tried it in Blender cuz' I got curious but the sim's face won't show? I'm not planning on making it right now but I might use it in the future! If someone could link a tutorial (or make a quick tutorial) that would be really kind, thanks!