If it is like the XIV, the torque arm comes off by removing the end cap.
The end cap is pressed in, so it can either be removed by sliding a blade between the cap and the arm and cantilevering it, or by using a special pulling tool that expands inside and then pull it out.
But you can try the first method to pry the cap off the arm. I will dig up the tool they mentioned to me a while back...
I was actually thinking about that, and was wondering if the Rotor could be slid in place, but that is clearly not the case, so it seems Kindernay would be better off delivering the Hub with the arm not mounted.
I actually asked them a while back to deliver mine that way as i will be making a torque arm adapter.