Authentication using LDAP and user names with dots

I already tried to post this question earlier via the ObjectWeb Sympa interface, but did not see it back in the archive list, nor did I get a e-mail confirmation. So please excuse me if it is posted twice now. I am currently evaluating XWiki for deployment in my company. So far everything looks great, but I ran into a blocking issue. I have setup XWiki to authenticate with LDAP, which is a requirement for us. The user names provided by our LDAP server all have dots in them, like 'eric.ter.haar'. XWiki seems to have a problem with this. When login in for the first time it creates a new user name that is equal to the part after the last dot, e.g., 'haar'. And it creates a space with the other part, like 'eric.ter'. The next login fails but without any notice. Does anyone know how to get around this? Thanks, Eric