You'll need to set it like so:
in didFinishLaunchingWithOptions:
tabBarController = (UITabBarController *) self.window.rootViewController;
// Set the color of the navigationbar in moretab
UINavigationController *moreBar = tabBarController.moreNavigationController;
moreBar.navigationBar.barStyle = UIBarStyleBlack;
or the other properties...
moreBar.navigationBar.tintColor = [UIColor orangeColor];
moreBar.navigationBar.hidden = NO;
moreBar.navigationBar.backgroundColor = [UIColor blackColor];