International Shipping from UK

[Pete-H]

We are looking at producing our own commercial invoices via Order Printer for exporting.  However Shopify only supports a 6 digit commodity code.  Has any one any experience of a workaround for this?  Or even an app that can do the job for us?  Can't see how we can use the data from Shopify as it truncates a 10 digit code to a 6 digit code even if it's imported or entered using Bulk Editor.