title: How to trigger "Set as profile picture" dialog (in facebook sdk/fbml)?
body: <p>in my last question I've asked how to set (write) a "generated" picture as profile picture in facebook. The answer was 'not possible'.</p>
  
  <p>Now I need to know: But <strong>how do I write my code to get a button "Set this picture as profile picture", which triggers me the core function from facebook?</strong></p>
  
  <p>I have seen this so many times in user apps, but I don't finde anything about it in the API.</p>