By default customer address fields are set at website level rather than store level. I would like to add the customer tax/VAT field to show on one store view ("codice fiscale" for Italy) but not have that field show with other store views.
I have tried copying the core 'customer.xml' to somewhere local, amending it to show tax/vat at store level. That shows the needed changes in admin system config but it does not work in the front end. I now have the tax/VAT box showing everywhere on the front end.
Additionally I would like to add a regex validation for the 'codice fiscale' using the latest 1.9 theme. I think I can add the custom regex and get it to work, however if anyone has any advice on setting customer address options at store level that would be most helpful.