title: leftBarButtonItem in UINavigationItem
body: <p>I've looked through several threads and come to a solution that I thought would work.</p>
  
  <pre><code>UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"backbutton.psd"]
                                                                 style:UIBarButtonItemStyleBordered target:self
                                                                action:@selector(barButtonBackPressed:)];
  self.navigationItem.leftBarButtonItem = backButton;
  </code></pre>
  
  <p>This gives me nothing.</p>
  
  <p>When I add this it gives me a regular blue bordered button (which isn't what I want) with the text "Back":</p>
  
  <pre><code>backButton.title = @"Back";
  </code></pre>
  
  <p>I don't get it.</p>