title: Set app.config parameters from a Visual Studio 2008 Setup project
body: <p>I have a WinForms application that uses a config file to specify where it's external files will be created.</p>
  
  <p>Is it possible to use the installer to question the user where the files should be located and  add this value to the config file?</p>
  
  <p>It would also be good if I could confirm that the user has entered a valid path but that's just a "Nice-to-have" at the moment.</p>