title: How can I restrict a transition in the workflow to only the user that created the work item in TFS?
body: <p>This is part of a larger restriction, but the part that is tripping me up is being able to allow only the user that created a work item (the value of the "System.CreatedBy" field) to transition a work item to the Closed state.
  I am aware of how to restrict the transition using the "For" and "Not" clauses, but those are limited to groups.  I want to restrict it to the specific creator of THIS work item.
  VALIDUSERS is also limited to groups (either TFS or AD).
  Thanks for your help.</p>