title: How do I take over a value sent by a "null form" redirecting to another controller?
body: <p>This is my form:</p>
  
  <pre><code>echo $this-&gt;Form-&gt;create(null, array('url' =&gt; '/offices/addOffice'));
  echo $this-&gt;Form-&gt;input('id', array('type' =&gt; 'hidden', 
                                      'value' =&gt; $this-&gt;data['Agency']['id'])); 
  echo $this-&gt;Form-&gt;end(__('Add Office', true));
  </code></pre>
  
  <p>Now in the addOffice function I would like to get the value sent from this form.</p>
  
  <p>What I did is:</p>
  
  <pre><code>function addOffice($id = null){
      $this-&gt;set(compact('id'));
  }
  </code></pre>
  
  <p>but it doesn't send the $id to the view. What am I doing wrong?</p>