I'm having some difficulty getting a workflow going.  I have a field on our sales orders called "Expected Date" which is just a date for when we expect the order to ship, regardless of the customer's due date.  Since we never plan for an order to be late, this date is always the same as the due date of the order until it is updated later.

I've set up a workflow to set the date to automatically match the due date on the order, however I've yet to get it to work.  Here are my parameters:

Basic Information:
Name  Create Expected Date