A client site has been barred from using Paypal, so their WP-e-Commerce catalog/cart now has to use manual EFT bank payments to accept money from customers. A customer receives this banking information in their order confirmation email.
When a customer makes an EFT payment through their bank website, they have the opportunity to insert a reference to accompany the payment. This is a string of text.
We'd like to send the order number in the order confirmation email, so the customer can use the order number as the EFT reference, so the client site can match EFT payments and orders.
How do we insert the order number into the order confirmation email?