I checked the manual for the D800, D600 and the new 70-200 f/4 but did not see a specific reference to VR activation using the AF on button. I did not notice any reference to VR activation half depressing the shutter button either in the camera manuals. But it works with all of my lenses. It also works using the D600 AF-L button (it does not have a separate AF-On button). You can hear a faint humming with activation - just like with the shutter release being depressed half way.
Sounds like a good design decision that needs to be updated in the manuals.