Custom transparency

[WazorRazor]

So I currently wanted to try a new program for my customs. It seems easier and better. I made it to transparency and it showed the Alpha Channel transparency. I saved it as a png. Then I opened up my trillex and edit the custom and replaced it with my new custom. & then It looks like this, Is this transparency or not? I'm just wondering, due to the color of the background. & I edited on reg paint. & opened it on gimp. and re-edited and transparent it a bit more. If you can help to get this background transparents
+rep

[MentaL]