I have been unable to get 6 cards working on a system despite trying BAMT/Win8/Win7/SMOS for like 2 days. I had to settle with 5 cards per rig, which ultimately made me have more rigs because of not being able to have 6 cards in one.
Not directed at me, but I'll respond anyway.
The biggest surprise I had to get 6 gpus running in one rig, was that I had to use a presence detect short on slots that were described as not needing them (mb z77a g65). Oh and if you do use presence short, dont f**k up your pcie slots by forcing some extra wire into them. Simply cut & connect the appropriate wires in the riser, much simpler and less invasive. Connect B17 to ground (B16 or B18 will do just fine, no need to go to A1).
Use a win98 boot usb stick with "atiflash -i" to see if they are detected by 'the hardware'. If they are, but do not show up in windows, or report error 43, it's a driver thing. If they do not show up for "atiflash" you'll probably need a presence short. No amount of driver juggling will help you in that case.