[Samba] sync Samba4 with Samba3 users?

[Tomasz Chmielewski]

I have a running Samba3 domain called "SAMBA".

I'd like to have an Active Directory domain called "AD" trust "SAMBA" 
domain.

In other words, if my Samba3 users want to log in to a Sharepoint server 
in AD domain, Active Directory should try to find the user in "SAMBA" 
domain and let him (or not).


As I understand correctly, AD can't fetch users ("trust") from Samba3?

Therefore, I'd like to set up a Samba4 server which would have users in 
sync with Samba3; then, AD would connect to Samba4.


How can I make Samba4 server enumerate/sync the users available on a 
Samba3 server?


-- 
Tomasz Chmielewski
http://wpkg.org