Don't you have a geosphere option in 3dsmax?
I thought making the planet was easy in 3ds max; IMHO, it was the texturing that was a pain in the arse.
Edit: I know you said you wanted to make planets in SEV, but if you want only to add a planet onto a picture, here is a good tutorial on how to make cool-looking planets with photoship 7.
http://gallery.artofgregmartin.com/t..._a_planet.html