That works for existing customers who can simply login.
However, I am not sure how new customers can register without losing the ability to be directed back to the cart.
The problem is that if a new customer needs to register they are directed to the register page. From their they proceed to login.
I this stage, they would go back to the control panel.
This creates a problem as I still think it would confuse some customers.
Is there a way of allowing a customer to register and login as a new customer, and be directed to the cart page?