Unfortunately, Documents Seller does not support Taxes . It was designed to sell digital download products, so I didn't think about taxes or shipping .
Could you explain more detail about your requirement about taxes ? Is it based on products or based on total price of the order ?
Right now I just need to add tax on the shopping cart subtotal. So regardless of state, everyone gets charged a certain tax percent rate on the total product amount.
I am able to hardcode the calculation for the authorize.net total so the correct amount gets charged to the credit card.
However I am having trouble updating the total_amount field in the database. Can you point me in the right direction?