If your enterprise should not require in commercial way a furnished business concern and if you should not be able voluntary to be registered into the trade register, then you are non--buyer. In this case not the commercial code (HGB) applies, but the civil law book to you (BGB); in the controversy you must prove however if necessary this to your business partner. As a so-called non--buyer you have the possibility of requesting the entry into the trade register and thus buyer of becoming. To you then the HGB with all rights and obligations applies.