Is there a "How To" out there for using Email Notifications with Match Exceptions as we have set the

I am trying to use Email Notifications with Match Exceptions.  I have created a new rule for "No receipts found" and named it "RULE_R510" and checked the Workflow and Email Notification checkboxes on the new rule.  I have also attached a query to provide the REQUESTER_ID from the VOUCHER_LINE table.  I have inserted this new rule into a new Match Rule Control and attached the new Match Rule Control to the BU I am going to use for testing.

I have entered a Req, created a PO, entered a Voucher and run Matching for the BU in question with the Workflow/Email Notifications option set but no email is sent.  I have checked that the Requesters Userid has Workflow and Email Notifications switched on.