Have you tried going through the example file they linked to in that thread? In theory it should be pretty straightforward. Just parenting 3d layers to a 3d null at the center of the "sphere" and rotate the null.
I tried, however, the trees only spun in place. The way you said it though makes more sense than what I did. I had the sphere rotating, and tried to rotate the null and trees separately, but I think both the sphere and the trees need to match the rotation to the null. I don't think I tried that. I will give it a shot tonight, when I am able to focus on that project. Thank you again.