You seem to have the same problem as I am having. Maybe you have seen my thread.
The key is the Displayport connection. This needs to either be to a Displayport monitor or have a special adapter.
There are two adapter types to change a Displayport to DVI (or Displayport to HDMI). Passive ($15 - $20) and Active ($100+). You HAVE to have an Active one. You will know it is Active because there will be three connections.
3. DVI (or HDMI)
AMD lists approved dongles, but within that list, for Eyefinity, you have to choose an "Active" one.http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx
Good luck on finding a Displayport monitor or an Active Displayport to DVI adapter. I have been looking hard. Every site is out of stock.
Sort of makes me sick. Hype hype hype and no product.