There was an option in the Samba plug-in, not sure if in the general settings or in the option of the single share.
I also found this:
QuoteOn a Samba share (Unix implementation of SMB/network share protocol) you will also need these additional steps, because by default Samba do not store folder attributes.
- First make sure Samba stores DOS-style permissions (like "read only"), by adding this line on your share definition (/etc/samba/smb.conf):
store dos attributes = yes- Restart Samba (sudo service samba restart)
I think the option was to enable DOS-style permissions