Printer authentication failed -- with alias

Hi!
OES 11 SP1 on SLES 11 SP2. Is there a way to authenticate for iPrint using user object alias?
I'd add - as requested - "AuthLDAPDNDereferenceAliases never" into iprint_ssl.cong, also checked in LDAP server object "Dereference aliases when resolving names for authentication", restarted Apache, refreshed LDAP, but ... still nothing. Should it be possible to make happen?
More thanks, Alar.