[Samba] Samba4 + OpenLDAP + Dovecot

[Markus Bajones]

Hello Samba list.

I have a question which I am unable to find the answer in the world wide 
web.
My current setup I wish to upgrade is as follows:

OpenLDAP with user acount information (names, passwords, etc.) against 
which Linux and Windows clients do authenticate.
Cyrus with its own user account information (emails, aliases, passwords, 
etc.).

I want to accomplish a setup which gives me to possibility to store all 
user data in one backend and let all clients authenticate against.
So my question now is. Is it possible to setup a samba4 domain 
controller with openLDAP backend and extend the user data so that I can 
use kerberos authentication for my windows and linux (ubuntu and debian) 
clients and let dovecot get its authentication information from the same 
ldap directory.
Also I would like to know if I have to store the userpassword in more 
than on ldap field (one for kerberos and one for dovecot). If so, how 
can I keep this two passwords in sync ?

I am grateful for any hint.

Thanks in advance.
Markus