wow, i have this same problem, i think. clean install 7.3. created users and group w/ users as member. crewated ibay for the group write, readable by everyone.
i mount the ibay in fstab from ubuntu wit dir&file_mode=0775 but anything copied or created is done so as 755, producing errors in apps like f-spot.
any ideas why this could be? why can't i create files/folders with perms 775 when mounted as such?
many thanks,
--matt
ps... line from fstab (and if umounted and mounted from ui, same result)
//smeserver/media /mnt/media cifs uid=smematt,gid=smemattsharegroup,user,iocharset=utf8,user=smematt,password=thepassword,file_mode=0775,dir_mode=0775 0 0