I would like to accomplish the following workflow:
1. Administrator creates an invoice for a customer. This is added to the customers account and an email is sent making them away.
2. The customer can login to see his/her "unpaid" invoices
3. The customer can pay the "unpaid" invoices and their status is automatically marked as "paid".
Is this something that Ubercart can naitively support or is there a relatively easy way to achieve this?