Remove payment from cart process and invoice after manual shipping cost added

[epidote]

It sounds counter to the automated nature of a shopping cart but I have a client who wants their customers to order through Prestashop but only get to the shipping step in the cart process. They then place an order which is then manually modified for shipping and availability after which time the customer is sent an invoice for payment.

 

Any ideas for a module that may help with this? Or even an idea of what this might be described as? Since it is essentially ignoring the stock control and shipping functionality that is built in to Prestashop it seems odd but might have already had applications elsewhere?

 

Thanks

Andrew