white space on top of UITabBarController

I need to add a UITabBarController as subView. But I can't remove the white space o开发者_如何学Cn top. Does anybody know a solution?

Thanks, Andreas

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This is what I do..

tabBarController = [[UITabBarController alloc] init];
tabBarController.delegate = self;
[tabBarController.view setFrame:CGRectMake(0,0,320,460)];