decals like udk

Trying to place decals on my model in 3DS max. I've found a few tutorials on how to do this, but they all use the uvw unwrap + composit material method, which isn't usable in a game engine because it requires the texture coordinates to be out of the 0,1 range.

Any ideas on how to do this? Perhaps a method similar to the UDK, where the decal gets projected onto the object instead of being added to the material?

Cheers for help in advance