Can you run 800x480 in windows? If you can, try installing powerstrip and exporting the linux mode line for it and see if it matches the ones you are trying below. You might be lucky and one of the parameters are slightly different (even though really it should make no difference :-)
The other solution is to put say a geforce into your eden if the video card will still not like doing 800x480.
Hope this helps!
Originally Posted by hkrebs