This might be usefull for someone. In default NAV, you can archive sales orders (it gets archived, when/if "Order Confirmation" is printed).
However, to fully use this functionality, user should firstly release order before printing.
I have noticed, that if sales order is not released before printing order confirmation, then document will be archived with amount equal to 0. However, if sales order is released and only then archive - archive will have all information you had on your sales orders.