[Samba] winbind does not work+sernet package+samba 4.2

[Yanni]

Here it is:

[root at jimmy samba-4.2.3]# systemctl status sernet-samba-winbindd -l

sernet-samba-winbindd.service - LSB: initscript for the SAMBA winbindd
    Loaded: loaded (/etc/rc.d/init.d/sernet-samba-winbindd)
    Active: active (exited) since Τετ 2015-09-09 10:10:53 BST; 3h 47min ago
   Process: 30692 ExecStop=/etc/rc.d/init.d/sernet-samba-winbindd stop 
(code=exited, status=0/SUCCESS)
   Process: 30698 ExecStart=/etc/rc.d/init.d/sernet-samba-winbindd start 
(code=exited, status=6)

Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk systemd[1]: Starting LSB: 
initscript for the SAMBA winbindd...
Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk sernet-samba-winbindd[30698]: 
/etc/rc.d/init.d/sernet-samba-winbindd wants to start but 
SAMBA_START_MODE is set to "none".
Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk sernet-samba-winbindd[30698]: 
Disable /etc/rc.d/init.d/sernet-samba-winbindd or set SAMBA_START_MODE in
Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk sernet-samba-winbindd[30698]: 
/etc/default/sernet-samba to "classic".
Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk sernet-samba-winbindd[30698]: 
Exiting gracefully now.[WARNING]
Σεπ 09 10:10:53 jimmy.testad.bio.ac.uk systemd[1]: Started LSB: 
initscript for the SAMBA winbindd.

 From the output I can see that winbind does not start because 
"SAMBA_START_MODE" is set to "none". I found this file 
/etc/default/sernet-samba and set "SAMBA_START_MODE" to "classic" but 
winbind still does not want to start. The same result when is set to "ad"

Changing the "none" to either "ad" or "classic" in 
/etc/default/sernet-samba I run: systemctl status sernet-samba-winbindd 
-l and it outputs the same information as before:
Σεπ 09 10:10:53 jimmy.testad.biosci.bbk.ac.uk sernet-samba-winbindd[30698]:
/etc/rc.d/init.d/sernet-samba-winbindd wants to start but 
SAMBA_START_MODE is set to "none".

Is /etc/default/sernet-samba the right file to edit?

Thank you