Make sure in the PM console you have the 'advanced' view check in the view menu.
when you say 'provisioning does not work' what do you mean? you cannot run provisioning jobs? the jobs fail?
Yes, it really was that easy: advanced view !
The provisioning starts and then stopped at step 14 of 16.
The reason was that the system package has been damaged. Maybe it has been caused by multiple PM sessions (for troubleshooting the 1st problem), from which we tried to provision and modify (the same) system package.
Now we use the advanced view and a new system package and everything works fine ...