I need an opinion on how to handle the VAT application based on your experiences.
I've a Magento 1.9.2 with only website localized in Italy thath sells all over the world to both businesses and private.
For European countries the VAT rate changes depending on whether th customer is private or bussiness why I need to manage 'customers groups' different related to their customer_tax_class on which I will base the taxation rules.
I think i have have this alternatives:
1) implement the logic of Magento (ver 1.9.2) and the "automatic assignment to customer group" following the VIES automatic validation of Tax ID
2) extend the code to make sure that the customer group is assigned based on a custom attribute (Private / Business) and leave the task backend operator to verify the correct indication of Tax_id where necessary (Italy and EU Business), perhaps by sending a notification when registering a new account and then making the 'Vat ID' field can not be edited from the user, but only from the backend to avoid variations or deletion of verified data.
3) to implement point 1 and extend code to make a regexp valdation in case of service unreachable or failure
Any ideas or suggestions?