title: fb:comment does not work on my application
body: <p>I'm a new Facebook developer. I want to add comments box to my application and I follow the tutorial in Facebook wiki. It's not work in my application. </p>
  
  <p>My canvas callback URL is <a href="http://122.155.0.71/~facebook/" rel="nofollow noreferrer">http://122.155.0.71/~facebook/</a> and I upload <code>xd_receiver.htm</code> to root directory.  I am using the following code</p>
  
  <pre><code>&lt;script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/XdCommReceiver.js?2" type="text/javascript"&gt;&lt;/script&gt;
  &lt;script src="http://static.ak.connect.facebook.com/js/api_lib/v0.4/FeatureLoader.js.php/en_US" type="text/javascript"&gt;&lt;/script&gt;
  &lt;fb:comments&gt; &lt;/fb:comments&gt;
  &lt;script type="text/javascript"&gt;FB.init("b6e07896a1d0889d9784dea150802587", "/xd_receiver.htm");&lt;/script&gt;
  </code></pre>
  
  <p>in my application. It not show up. When I view this page with Firebug. I see <code>&lt;fb:comments&gt; &lt;/fb:comments&gt;</code>. I don't know about xid, where can I create it?</p>