I seem to have the same problem as well. I'm using a Asus P5K-E/WiFi-AP motherboard(which also only support 1 PCI-E 16x and 1 PCI-E 4), and I can see that Crossfire is enabled in CCC, but not in GPU-Z. I did both the steps in removing and installing the drivers, but it's still the same.
I did...