I am doing exactly what you are supposed to do to make a 3D skybox and it is so off that I dont know what I am doing wrong. This is what I do, tell me if there is anything wrong with it.
-First I make what I want to be the skybox normal size.
-Then I put a skycam at origin 0,0,0.
-Then I select all the things I want to be in the 3D skybox, including the 3D skycam and copy it.
-I right click and hit "paste special."
-Then I click transform
-I scale it down to .0625
-I put my newly scaled down 3Dskybox in a box of the skybox texture.
-I put its own light enviornment in it.
-Then I delete the original big versions of the skybox and the Skycam in the actual map.
Is there anything wrong with that? It is off, here is a picture of what it looks like...
http://jupiter.walagata.com/w/masamune212/example.jpg