Ios 在工具栏上方弹出iAd

我有一个带有UINavigationController的应用程序，我将工具栏设置为可见。我想显示IAD，但它们总是从屏幕的最底部弹出。我正在调整尺寸-这是一份日志：

2012-10-08 09:52:17.722 Whos Here[21330:c07] INFO showBannerView:animated:
2012-10-08 09:52:17.723 Whos Here[21330:c07] INFO layoutAnimated with ADBannerView(#c14fed0, {{0, 436}, {320, 50}},  child of UIView(#c153930)
2012-10-08 09:52:17.724 Whos Here[21330:c07] INFO layoutAnimated content frame {{0, 0}, {320, 416}}
2012-10-08 09:52:17.724 Whos Here[21330:c07] INFO layoutAnimated banner frame {{0, 436}, {320, 50}}
2012-10-08 09:52:17.724 Whos Here[21330:c07] INFO layoutAnimated shrinking content frame {{0, 0}, {320, 366}}
2012-10-08 09:52:17.725 Whos Here[21330:c07] INFO layoutAnimated shrinking banner frame {{0, 366}, {320, 50}}

我是否在尝试做一些根本不正确或不好的事情，例如，对抗HIG

谢谢

史蒂夫