EU businesses exporting to other EU businesses need to generate intrastat invoices. Intrastat invoices have an Intrastat code against each items (products only and not services). Although we can add a custom field to hold this against the items Books doesn't allow to create an invoice template where we can choose to display the intrastat code column (custom field). We either have to set it on all templates or non. 

What we need is to be able to choose on each invoice template whether to show the custom field in the items table. This must be an issue for all EU based businesses who export to other EU countries because this is a legal requirement in the EU.  A simple code change on the invoice items table would make this work.