Hi!
Don´t know if this can help you but I think this person had the same problem as you:
Take a look at http://campingsex.org/ click on the top of the side on "8x8" and then on "3d rendering of 8×8". there you can see his project.
And this image http://campingsex.org/8x8/media/lamp_schematic.gif shows the schematic. there are also many information on the side, so perhaps you should take a look.
Poldi