title: Extend UIButton in monotouch
body: <p>i'm tring to extend UIButton class to add my id property.</p>
  
  <p>How i can do this?</p>
  
  <p>Problem is to create a button you use</p>
  
  <pre><code>var button = UIButton.FromType(UIButtonType.RoundRect);
  </code></pre>
  
  <p>so, if i've</p>
  
  <pre><code>public class MyButton : UIButton
  </code></pre>
  
  <p>how i can create my button?</p>
  
  <p>thanks.</p>