I tried out my Geotagger Pro 2 on my D800 and it seems to work fine it Auto mode.
The unit does not need to be mounted on the hotshoe, just connected to the 10 pin. When in auto mode turning on the camera turns on the GPS. When the camera is turned off the GPS stays on for one minute before going back into auto mode.
Did you get your Geotagger direct form Solmeta? I got mine from the Nikonan store.