[Koha] Use and setting of userid in borrowers table

Yesterday, I installed Koha which I hope to be using for our small internal library. I set it up in such a way that it will use cookie authentication, thus using the borrowers table. I was wondering the following: 1. Is it possible to set the userid and password from the web interface; I'd rather not use the card barcode to login to the system. 2. I saw that one can set different flags for each use to allow for access to different parts of the intranet interface. It seems, howver that one needs super librarian status to login anyway. Is this a bug, or am I doing something wrong? I hope somebody can help me. Cheers, Marcel