title: how to ask webapi for a specific content type
body: <p>as I understood from ASP.net MVC 4 Release notes, is that it has <strong>Content Negotiation</strong>, and that it will return the <strong>content type requested by the client</strong></p>
  
  <p><strong>how is the client asking for a specific content ?</strong></p>
  
  <p>(in my case would be flash asking for XML, using AMF)</p>