I know, I shouldn't be using it in the first place, but I had no alternative until recently.
I think I have a really precise image of the development process of the fglrx drivers since I nave been successfuly using sleep with 8.33.6. That went down the drane with 8.36.5. After a month of pain (I don't understand why it took me sooooo long) I decided to go back to the version that worked (which was a package I prepared myself).
Matthew Garrett told me at DebConf that the avivo driver should work for my video card, but it needs pciaccess which is not available in Etch and at that time was not available even in experimental.
At some point I'll probably use avivo, but until then I still want my laptop to be able to sleep... I hope AMD opens those drivers soon.