title: Orbeon - how to validate file content uploaded by user
body: <p>I need to validate content of pdf file sent by "File Attachement" component, using Webservice, uploaded by user.</p>
  
  <p>How to do that ?</p>
  
  <p>Action Value Change is not called</p>
  
  <p>ver.orbeon-4.4.0.201311042036-PE
  Thanks
  Piotr</p>