I'm gonna have the answer to that soon when I finish this next mission map I am working on. Ya see, you can add custom skins into a map and then when you "build" it, that custom skin replaces the default skin. It's always worked for Offline & custom maps for AvA, FSO, etc. I'm anxious to see if it will work for the missions. By all accounts it should, but the skin HAS to be part of the map, not one someone adds later.