[TYPO3-commerce] Backend-User has no rights to edit an article.... BUG ?

[Frank K.]

I created a Backend-User, which should be able to handle the shop (create 
new categories, products, ...),
this all works fine (even deleting products) but it crashes when this User 
tries to edit an article ("Sie haben nicht die nötigen Rechte, um diese 
Änderung durchzuführen." // You have not the required rights ....)

The User has all Right I could give him, but he is only able to change an 
article when he is set to admin (what he should not be).

Does anybody else have this problem ? What can I have overseen ??