So I tried this myself last night, if you're still looking. But as you said, the parts just turn black. I erased the texture, applied alpha masks and other ways, but it still wouldn't "remove" it. I tried on some other armor pieces (lucatiels mask) but no luck. I looked around and other people agree, but there is something else affecting, or determining the alpha as well, besides the texture. So if you did get this to work, let me know. But other than that, sorry.