Thank you Michael, I think I have a beginning of answer.
Budypress is really heavy and multisite too. I have activate Buddypress only for one subsite. That’s true.
However I’m Super Admin so all my test and work are done as Supeadmin ;o)
So… I have activate BP and your plugin in the main site. And indeed your settings appear in admin menu but always for the main blog.
I have try in sub-blog but doesn’t work. Nothing in admin menu and if I do subscription (in an other browser as visitor), subscription is accepted. No moderation.
So it means your plugin doesn’t work in subblog in Multisite. (WPMU)
Do you think you can solve this problem… quickly ???
Dominique