AEU MX Effect?

Hello, I was looking at my Download Package of "Airport Environment Upgrade MX", and was looking at the textures. I came to the conclusion that what FS was doing was take an undetailed bitmap with the basic material pattarn on it, and then overlaying a repeated "whats the word here, um?" - detail map on top of that to give the surface the feel of a real material if you catch what I am saying. Can we use this technique in 3rd Party Scenery, and how many of these "Detail Maps" can you have? I'm a newbie, I like the ffect very much :D