Developer in PrestaShop (Experts in PrestaShop only)

I need to have a VAT alternative that calculate VAT based on the profit (VMB) on the product: (Sale Price - Purchase Price) * 0, 20 = VMB If this option is selected the customer shall see produts as it is not WAS at all. If the customer buy another product with regular 25 % VAT the customer will see VAT on this product. --- Exempel: A customer buy 2 products: Product 1(With VMP) Sale price with VAT: 200 Our purchase Price: 100 (Invisible to the customer) VAT: 20 (Invisible to the customer) Product 2 (With regular 25% VAT) Sale price with VAT: 200 VAT: 40 Shipping (With regular 25% VAT) Sale price with VAT: 100 VAT: 20 SUM: 260 Shipping: 80 VAT 25%: 60 Total: 400 --- But it is important that the VMB-VAT also will be transferred to my accounting ([login to view URL]) If you have used [login to view URL] before you can also get the job of creating a module for transmitting the invoices for PrestaShop to the accounting system. (I want to make this as a separate project) Important that this will be made ​​into modules that are easy to install, then I will make a several stores that will use the modules.