добавление более двух кнопок на панель навигации

Я пытаюсь это сделать, но это не работает.

-(void)viewDidLoad
{
    // create a toolbar where we can place some buttons
    UIToolbar* toolbar = [[UIToolbar alloc]
                    initWithFrame:CGRectMake(0, 0, 100, 45)];
    [toolbar setBarStyle: UIBarStyleBlackOpaque];

    // create an array for the buttons
    NSMutableArray* buttons = [[NSMutableArray alloc] initWithCapacity:3];

    // create a standard save button
    UIBarButtonItem *saveButton = [[UIBarButtonItem alloc]
        initWithBarButtonSystemItem:UIBarButtonSystemItemSave
        target:self
        action:@selector(saveAction:)];
    saveButton.style = UIBarButtonItemStyleBordered;
    [buttons addObject:saveButton];
    [saveButton release];

    // create a spacer between the buttons
    UIBarButtonItem *spacer = [[UIBarButtonItem alloc]
        initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace
        target:nil
        action:nil];
    [buttons addObject:spacer];
    [spacer release];

    // create a standard delete button with the trash icon
    UIBarButtonItem *deleteButton = [[UIBarButtonItem alloc]
        initWithBarButtonSystemItem:UIBarButtonSystemItemTrash
        target:self
        action:@selector(deleteAction:)];
    deleteButton.style = UIBarButtonItemStyleBordered;
    [buttons addObject:deleteButton];
    [deleteButton release];

    // put the buttons in the toolbar and release them
    [toolbar setItems:buttons animated:NO];
    [buttons release];

    // place the toolbar into the navigation bar
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]
            initWithCustomView:toolbar];
    [toolbar release];
}

Как я могу решить эту проблему?