Drupal 7 and Ubercart - admin approve sale before payment Drupal 7.36 &amp; Ubercart 3.0-rc4.

My client needs to vet users purchasing products from an Ubercart shop. The idea is that when the user completes the checkout, the user does not go to a payment gateway - but instead, the admin receives an email notification saying someone wishes to make a purchase. the admin then goes on to the site and authorizes the sale, sending an email to the user telling them they can now return to the site and complete the purchase and pay.  

I've looked at rules, but it appears for fall slightly short of what i need.

Are there any contrib modules, or and know workarounds for this?
I think you can do this by using Rules module.


  The Rules module allows site administrators to define conditionally
  executed actions based on occurring events (known as reactive or ECA
  rules). It's a replacement with more features for the trigger module
  in core and the successor of the Drupal 5 workflow-ng module.



You need to create a rule with below condition :



  Condition : Data comparison for the order state "Approved by admin" with
  a Negate option (checkbox in bottom).


So if you change the order state to "Approved by admin" this rule will not trigger anymore because this condition will return FALSE.