I've dealt with only one Haas rotary. They have about a dozen different models. So what I say may not apply to the table that you're looking at.
1. Weight. The RT may actually weigh more than the maximum allowable for the Tormach's table.
2. Complexity. The Haas table used a servo instead of stepper. And it had pneumatic locking that was controlled by the mill. The mill would look ahead at the code and know when to unlock the table so the motor could rotate it.
Assuming it fit on the table and didn't overload it, you'd have a serious programming and wiring job on your hands to make it work.