Create an Invoice linked to an Order

Question:
Using Velo - how can I create an invoice that is linked to a bookings order?

Product:
wix-ecom and wix-billing

What are you trying to achieve:
I have a workflow that creates bookings and then creates orders for the bookings. I would also like to generate an invoice for the order and send to the customer.

What have you already tried:
I can create an Invoice but cannot figure out how to link the invoice to the order. I have tried using order._id as the Invoice id (as I noticed this was the case for invoices generated from an order in the dashboard).

Additional information:
Obviously this is possible if it is being achieved through the dashboard, but I cannot figure out how to replicate this in code. Thanks!

Can I assume the radio silence is because this is not possible? What about changing the status of a bookings order to unfulfilled…or fully edit an order…am I missing something?