Yes I believe that is true. Passwords are not stored in LDAP. We too use IMAP auth, and it does work nicely, but, it does not pull in the users details (name, etc) from SME. Which would be nice.
What I am trying to do however is only read and write the egroupware address book in LDAP. I have seen several posts in other forums about this working with openLDAP (which is installed in SME).
I just have not be able to put together the steps to get it to work.
If anyone has any ideas please let me know!
Kevin