Eusira, you have no moderating powers. I've told a moderator for what your trying to do.
As for masta, I've told you to do searches in the forums millions of times. If you continue to ask questions like this in trouble, you'll get in trouble.
First of all, .blp and .mdx ARE SEPERATE.
The SKIN is the wrapping of the main model WHICH IS NOT ALWAYS enabled to EDIT any part of the skin.
Second, THE .MDX MODEL is the Main model WHICH can be edited WITH A MODELLING PROGRAM AND IS NOT IN .BLP.