How do I add the SKU to the checkout page?
The SKU is properly visible in the "product in cart" page. But then going to checkout the SKU does no longer show up. Having searched a lot I cannot find any method to add the SKU on the checkout page. The SKU is very important, it must be available on the final invoice as reference and will be used as reference in the payment process.
Has anyone any idea how to add the SKU to the checkout page?
PS: This is the second missing function related to SKU for something which should be extremely simple... the first was that I cannot sort the product page on SKU.