title: How to add MKUserTrackingBarButtonItem in Interface Builder
body: <p>Would anyone be able to show me how to add a <code>MKUserTrackingBarButtonItem</code> to my toolbar in Interface Builder?  I have a <code>UIBarButtonItem</code> on my <code>UIToolbar</code> whose class I have set to MKUserTrackingBarButtonItem, but this doesn't seem the right way to do it.</p>
  
  <p>I have the following property:</p>
  
  <pre><code>@property (nonatomic, strong) IBOutlet MKUserTrackingBarButtonItem *trackingButton;
  </code></pre>
  
  <p>And I can add the button in code by using:</p>
  
  <pre><code>trackingButton = [[MKUserTrackingBarButtonItem alloc] initWithMapView:mapView];
  NSMutableArray *items = [[NSMutableArray alloc] initWithArray:toolbar.items];
  [items insertObject:trackingButton atIndex:0];
  [toolbar setItems:items];
  </code></pre>
  
  <p>But I'm just missing how to do it in IB.</p>