title: UIApplication removeStatusBarImageNamed doesn't work
body: <p>i'm working on a jailbroken iphone with iOS 5.0.1, just want to access status bar image,
  and my code is as follows:</p>
  
  <pre><code>-(void)addStatusBarImage
  {
  
      NSLog(@"addStatusBarImage");
      [[UIApplication sharedApplication] addStatusBarImageNamed:@"sgtest" removeOnExit: YES];
  
  }
  
  -(void)removeStatusBarImage
  {
  
      NSLog(@"removeStatusBarImage");
  
      [[UIApplication sharedApplication] removeStatusBarImageNamed:@"sgtest"];
  
  }
  </code></pre>
  
  <p>my problem is, the add function works fine, but removeStatusBarImageNamed seems useless as the "sgtest" image still exists in the status bar unless my app is terminated. </p>