Must I do anything special in order to show a modal view controller?

I have a UIViewContro开发者_如何学Cller as root vc, attached to the window. Then I simply created another VC and want it to appear modally. When I add this directly to the rootViewController, it is visible. But when I call

- (void)presentModalViewController:(UIViewController *)modalViewController animated:(BOOL)animated

nothing happens.

Inside the vc do you go?

NewViewController *myNewViewController = [[NewViewController alloc] init];
[self presentModalViewController:myNewViewController animated:YES];
[myNewViewController release];