In "users>permissions>user policies" is a selection "Creator's role in new courses". I just tried "teacher" and "Kursverwalter+" (thats the name of my new style course creator) to make shure that this is not the problem.
...i just tried it and found the following: If i select in "users>permissions>user policies -> Creator's role in new courses = Teacher" then i can create the course and view him, administrate him and so on
Thanks, your questions got mee on the right way!
So this problem should not exist anymore.
But the other problem is still present: With that new role i dont have any access to the "old" courses, even if i have the role "Kursverwalter+" (new role with the course creator role as a base and with the additional rights for course backup, recovery rate and course import) in that course category.
So it seems that Moodle keeps something like an owner of the course besides all that roles.