I'm using CCK (Filefield), Drupal 6 and Ubercart: User buys a node, he comes back to that same node, a PHP function checks if the user has bought the node, if yes, it gives the user File Access to access that specific CCK field on that specific node, if not, everything stays the same. My FileSystem is private.

Can I do this with this module? If yes, how? I can't seem to understand how it works.