So have you been able to get this setup to work? Others I have talked to thought that the antenna in the back would interfere with the mounting of the camera on the grip. Also see this thread, by @Kev Waite
I would be concerned about damage to the RF board with no antenna connected. I'm not even sure how the antenna is mounted. Is it screwed onto a connector? If so, a flexible antenna could be used instead of the mushroom.