When I select it all that's activated is Multi-GPU.
You realize that Multi-GPU is probably just another term for SLI they use with the 690.
They are labeling it slightly differently for the 690, but I'm quite certain that Multi-GPU is what you want.
You should also be able to look at GPU-Z and see SLI enabled there. If GPU-Z doesn't recognize it as SLI, there could be a problem. You should also be able to run benchmarks to confirm.
The graphics score in the detailed read out of 3dmark11 should be about 9000 with 1 GPU, and around 18000 in SLI.