Hi, John.
Cache Refresh doesn't copy any passwords from backend into Gluu's internal LDAP directory (actually, in case of AD it isn't possible to achieve with LDAP requests at all; you need to use its APIs for replication, that's the only way, AFAIK). It just aggregates user attributes from several sourse backend LDAP servers, and, optionally, run transform script on this attributes before saving them internally. When authenticating some user who was imported by CR from backend, oxAuth will anyway test its credentials against backend (after making sure that such user exists at all in Gluu's internal LDAP directory)
Regards,
Alex.