Automating Duty Rates calculation and allocation

Hello, we are going through the Netsuite implementation process and we are currently facing an issue with the automatic duty rates calculation and allocation to our Landed Costs. We are using the inbound shipment module for our containers and the systems seems OK when it comes to carriage inward allocation based on the value of the products on a container.

The problem comes when we then want to calculate and allocate a duty rate (based on the commodity) to all products on that inbound shipment (calculated as follows: [total value of product + carriage inward allocated to that product] * duty rate % for that commodity). Currently we are only able to add these duty rates manually after the "receipt" process in the item receipt record by editing the entry and adding the correct value of duty (along with the carriage inward) to the product.