title: Cant set image to backBarButtonItem
body: <p>i have <code>UITableView</code> based application, and i can't set <code>backBarButtonItem</code> properly.
  Back button is button, which appears when i select any item, call second view with method <code>didSelectRowAtIndexPath</code>.  When i try to set it like this:</p>
  
  <pre><code>UIButton *back1=[UIButton buttonWithType:UIButtonTypeCustom];
      [back1 setFrame:CGRectMake(10.0, 2.0, 45.0, 40.0)];
      [back1 addTarget:nil action:NULL forControlEvents:UIControlEventTouchUpInside];
      [back1 setImage:[UIImage imageNamed:@"back_button.png"] forState:UIControlStateNormal];
      UIBarButtonItem *back = [[UIBarButtonItem alloc]initWithCustomView:back1];
      self.navigationItem.backBarButtonItem = back;
  </code></pre>
  
  <p>There is just back button with default style and somehow with title of my <code>TableView</code> controller window.</p>
  
  <p>When i set it like this: </p>
  
  <pre><code>UIBarButtonItem *backButton = [[UIBarButtonItem alloc] 
                                 initWithImage:[UIImage imageNamed:@"back_button.png"]
                                 style:UIBarButtonItemStyleBordered 
                                 target:nil 
                                 action:nil];
  
   self.navigationItem.backBarButtonItem = backButton;
  </code></pre>
  
  <p>There is an image, but, it look like "inserted" in default back button, doesn't look nice at all.</p>
  
  <p>Please help me.. i tried many ways to solve this, but, in many cases there is just default Back button with title "Products" (there is title which appears on top of navigation bar in my <code>UITableView</code>). Any help would be appreciated!</p>