Interesting. I think the one on mine is based on a similar concept. Not as neat as the one Old Magnet shows in the thread you linked.

 

It looks to mount to the existing drawbar as the pull point and has threaded adjusters on the outboard ends of the swing plate(?) brackets to keep the drawbar in tension. It doesn't seem to pull on any part of the lower rear case; only the two mounts at the top.

Hope I'm interpreting what I'm seeing right.

Paul.