title: "self.navigationItem.hidesBackButton = YES" not working with UITabBarController
body: <p>I have a UINavigationController with a UITabBarController nested within it. I'm trying to hide the back button in the navigation bar so that I could replace it with a custom button. But I can't seem to do this once one of the tabs is the active view. </p>
  
  <p>I've tried </p>
  
  <pre><code>[self.navigationItem setHidesBackButton:YES animated:NO];
  </code></pre>
  
  <p>but to no avail.</p>
  
  <p>Any help would be much appreciated.</p>
  
  <p>Thanks!</p>