material element configuration

Hello.

I have several different characters all based on the same mesh with a few changes, one of said models works OK when imported into unreal engine, in the next image you can see element 0 is assigned to the head of the model, I isolated element 0 so it is easier to see it.

The lower part of the same image is a different model and element 0 is now assigned to the body.

I need to be able to assign element 0 to the head and so far I been unable to do so.

Any help is greatly appreciated.

http://thumbs.subefotos.com/f6d28ca5e4cc39298da51466c24c0779o.jpg