I know very little about map making so I would go to gametoast also, but I believe you copy the files you want, for example, if you want the sky there is a cor.sky file I believe. Put this in the assets folder of your map I think. Double check the getting started guide. I know you can do what your planning on doing but I dont know how to do it, I tried doing the same thing on Jabbas but I never figured it out, as I said before, go to gametoast.com and go to the forums and then the modding section and ask.
"Everyone that posts here is aware of the game, thanks though." ET