Add a \"Credit note\" feature to ARTIO VM Invoices component - for Virtuemart 2

Hi, I´m currently using the invoice component "ARTIO VM Invoices" for order management in most of my Virtuemart 2 designs, but it lacks one important feature, which is an easy way create and manage order credit notes. Out of the box ARTIO VM Invoices only support 1 PDF invoice template with an WYSIWYG editor and there is no feature where you can easily create and edit a credit note PDF from an order in the system. What I want specifically is: 1. To add an extra PDF invoice template with an WYSIWYG editor specifically for credit notes. 2. To add a "Create Credit Note" button in the order list of ARTIO VM Invoices admin to all orders that have a PDF invoice generated in the system. 3. When you click the "Create Credit Note" button a popup must show where you can choose with checkmarks which products in the order you want to credit and also whether you want to credit the payment fees and shipping fees from the original order. Per default all choices must be checked so that you must deselect those products and/or order fees you don´t want to be credited before clicking "submit". 4. When you click "submit" a new credit note order must be created in the system, based on your choices, and the credit note PDF must be sent to the customer by email. The newly created credit note order must be given a specific order status called "Krediteret". 5. In the order list in ARTIO VM Invoices admin it must show a link to the credit note PDF on all orders where there has been made a credit note. Also, there must be a link to the original order PDF on all credit note order in the order list. 6. Finally, in the "Create Credit Note" popup form any previously credited products or fees must be grayed out and unchecked, so that you cannot by mistake credit something that has already been credited. I would love if this modification can be made as an installable plugin, so that I can easily apply this to all of my Virtuemart 2 designs.