The Rexofader prevents operation because:
adapter like third version of this image:

I can't mount it upside down because there is the lower part of Rexofader that prevents it.
The second version, that I also have, not fit well, for the same reason.
At the bottom of the Rexofader (in the "blade") there is a small hole, where the release cable can screw, but the internal thread of my cable can't push the switch to the end. Perhaps my cable version, original Bolex, has the thread too short, but I think if it were longer it could break.
What do you think?
Thank you.