Alright, you want to create a template from your texture, which will automatically become white/black. From there you would want to edit that template to be more to your taste to what you want chromed etc. Which can be done through another program, like photo shop. Once those changes have been taken place. Open your normal texture through DXT and import alpha, which would be you edited from photo shopped "black/white", export your alpha channel. When you export, your assigning that alpha to your base texture. Save your normal texture as a DX1 or DX3. I like DX3, second open your Alpha back up which you exported and also save it as DX3 and place both textures in your texture folder, "base, alpha". Hope this helps, just reply if you need more help/problems.