UserID upper/lower case access rights

[Kr1stom]

Hi

I'm using openID to authorize users and role-based strategy for the access rights management. The problem is that when users log in, sometimes they get the userID in uppercase and sometimes in lower case which causes role based strategy to fail giving the access rights to certain user if I haven't declared both userID's (upper and lower case). Does anybody know where this difference in logging in comes from? When is userID in upper case and when is userID in lower case?