Hi Carsten, first of all, django-dev is not a second level support list, so for the future please refrain from posting here just because you get no answer on the user list. As for the issue on hand, try accessing ma.vbp_id after you assign the instance, this should give you some clues.
Cheers, Florian P.S.: Also if you want your app to be reusable code in English and not in German ;) -- You received this message because you are subscribed to the Google Groups "Django developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at http://groups.google.com/group/django-developers?hl=en. For more options, visit https://groups.google.com/groups/opt_out.