If you look at this picture from xtreme you can see that the long arm from the ram to the rear plate comes out on the right side of the rear plate. You can also see that the normal rear plate on the transmission is in place at the bottom of the new plate. This is a simple three point in that the top link does not move up and down with the two side arms. It is only for stabilizing the load of the two arms. The new rear plate has to be at least far enough from the old tranny plate for the mechanism to operate. The new plate bolts to the out side of the rear end with bolts that go in from the wheel side into the housing. My guess is that some of the rear axle holes are used to support the rear plate. I am not sure how the lower hitch plate that has the trailer hitch mount on it bolts to the rear end. It would seem like there would have to be some bushings between the new plate and the old one to keep the old plate securely fastened to the rear end.

Cub cadet cat 0 3 pt on a 2182
 

I will have to check my manuals to see if I have the installation drawings for the 3 point hitch.

I have attached the pictures of my mount let me know if you need anything specific that I have not included. it does not have downward force by design I would suggest you set yours up the same way or provide a hydraulic float. let the tool do the work grading, tilling whatever.

Please let me know if you need a specific picture or measurement

The Cub Cadet Website should have a similar exploded view for the original system