Messaging server and external LDAP user store

Is it possible to have an external LDAP application store all user information and then have the messaging server authenticate against it and create a mail profile in it's own LDAP instance, similar to the way portal handles LDAP users? If not, what is the best way to store user information outside of the mail server instance? Create an LDAP instance and extend the schema to support the mail classes and then use replication to push the users into the mail servers directory instance?

[502 byte] By [708994] at [2007-11-25 7:08:07]