title: iOS 5 [UINavigationBar appearance] setBackgroundImage does not do work
body: <p>I created a new test iOS5 project in Xcode 4.2 Build 4D199 and tried to set the appearance of the <code>UINavigationBar</code> as described above, but nothing happens.</p>
  
  <p>The code I tried in the <code>viewDidLoad</code>:</p>
  
  <pre><code>[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:@"navbar-iphone.png"] forBarMetrics:UIBarMetricsDefault];
  </code></pre>
  
  <p>The only way I can get it to work is to set the appearance on the instance of the <code>UINavigationBar</code>.  Like:</p>
  
  <pre><code>[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"navbar-iphone.png"] forBarMetrics:UIBarMetricsDefault];
  </code></pre>
  
  <p>What is going on? Has anyone else had this issue?</p>