[Samba] setgid bit disappears

[Vicente Martinez de Cestafe Ochoa de Eribe]

I realise that the problem is a matter of linux (perhaps a security issue).
>From the console i do:

 # su user
 $ mkdir directory
 $ exit
 # chgrp new_group directory
 # su user
 $ chmod 2770 directory
 $ ls -ld directory

 drwxrwx--- directory   (setgid bit is not there)

And if i do chmod 2770 as root  setgid bit is there.

It seems that isn´t a matter of Samba. I apologize for the inconveniences.