It isn't that hard to create your own interface, but it depends on your knowledge in programs like Photoshop, or Gimp, etc.
If you know how to deal with those it is just some kinda time-killing, as it takes some time to create those alpha maps for the tga-files. You can do it in a simple way, just transparent and non-transparent, and you can create very complex gradient alpha maps. But again it depends on how experienced you are in the whole graphic stuff.
After I am finished with my "there and back again"-style I can create a tutorial how to do basic things in Photoshop, if someone is interested in.