Create a \'proof of delivery\' doc from an invoice on Sage One -- 2

I have Sage One.\r\nI can generate & print a Sage One Invoice for my customers.\r\nHowever, I also need to be able to generate & print a Proof of Delivery for when the stock items are delivered. All the details are on the Invoice, I just need a program written which can access & exact these details from the pdf generated invoice and on the back of this slot the details into a pdf proof od delivery pdf on a regular basis.\r\nI generate invoices everyday so the process needs to be quick, ideally I generate the invoice and then hit another button to generate the Proof of Delivery pdf.\r\n