/** * Get a static reference to the storage object associated with this model object * * @return the storage object */ public static function get_instance() { if (self::$so == null) { self::$so = CreateObject('rental.sobilling'); $virtual_file_system = CreateObject('phpgwapi.vfs'); $virtual_file_system->override_acl = 1; self::$so->vfs = $virtual_file_system; } return self::$so; }