<inser belt name> .blp, how to edit it properly?

[Diclonius]

Hey guys, I have a question, I wanted to edit a belt but the thing is that when I edit it is that I have a black "underpants" shall we say, something like this:



Don't mind the 1337 bankai text, the thing is that the black part under his belt is not the pants but a part of the belt itself and I want to remove that so that I only have the white belt, does anybody know how to fix this? I've extracted the mail belt part, converted it to png, changed the .png version and converted it back to .blp in the right way, so I haven't done anything wrong I think.

Tx beforehand.