title: Set presence as unavailable - Facebook Chat API
body: <p>I'm using xmppframework to develop my xmpp client. I make a normal login in Facebook, after that i setup my xmppStream to connect my client with the facebook chat and then, I send the initial presence as:</p>
  
  <pre><code>NSXMLElement *presence = [NSXMLElement elementWithName:@"presence"];
  [self.xmppStream sendElement:presence];
  </code></pre>
  
  <p>After that, I decided to implement the opposite behavior (set presence as offline), To do this, I have the following code:</p>
  
  <pre><code>NSXMLElement *presence = [NSXMLElement elementWithName:@"presence"];
  [presence addAttributeWithName:@"type" stringValue:@"unavailable"];
  [self.xmppStream sendElement:presence];
  </code></pre>
  
  <p>The first piece of code works and I'm visible to everyone after run it. However, when I try to set my account offline, it doesn't work. Basically, Facebook ignores my message.</p>
  
  <p>Anybody have an idea how can i solve this?</p>