This tutorial requires knowledge of how to reskin a model, Paint.NET and the VTF creating addon by Nemesis (http://nemesis.thewavelength.net/index.php?c=225).
So, have you had the problem where you want to make a model reskin or skin and have it glow in one area, but when it's rendered in-game, it glows all over? I have had that problem in trying to reskin the models in Portal, but now I have a solution!
1.Make sure you have the skin you want to glow opened up in Paint.NET.
2.Create a new layer above the first.
3.Go to layer 1, select the parts you want to glow, copy, and paste them into layer 2.
4.Click on layer 1 again, as if you were going to edit it (and you are).
5.There should be a pencil over a price tag looking logo in the bottom right side of the 'layers' tab. Click on it.
6.Once a new window has opened up, make sure opacity is set to 1.
7.You should barely (if at all) be able to see layer 1.
8.Save the product as a VTF *WITHOUT* animating layers in the folder your reskin belongs.
Try out your new skin/reskin and enjoy!