For our PDF based shipping method to international addresses, we have released enhancements to our system to fill in Harmonized Product Code and / or Country of Origin when filled in.
Country of Origin is a global setting, it is set in Teapplix "Setup => Shipping" page.
Harmonized Code is stored under Inventory => Products table. You can click on the "edit" link to fill out the info, or you can bulk upload the information.