[Samba] Samba4 changing a user's password from linux workstation

[Julien TEHERY]

Hi

I'm trying to find a way to change user passwords from ubuntu client 
workstation on a samba4 domain.
I tried in CLI from the client workstation (ubuntu 14.04) with:

- smbpasswd -U $user

=> In this case, password seemed to be updated, but "wbinfo -a" didn't 
worked with the new password, the old one was still active.

- samba-tool user setpassword $user
=> In this case i got a "ldb_search: /invalid basedn '(null)'/"


What's the proper way to change the users password from the linux 
clients in a samba4 domain?

Thanks for your help