now it works perfect!
But one more problem appeared.
I saved a post at the child instance, and it was given to revision to the mother instance admin, showed at: all posts. So far the way it should be.
But when I created another post at the child instance, it wasn´t showed at the mother admin instance at the post overview list.
What is the logic and admin setting to give all posts from child instances to the admin at mother instance to check there and publish at least?
Thanks in advance!