That behaviour is correct. The EU VAT Assistant is designed to show the VAT field for countries to which the intra-EU VAT rules apply. Switzerland is not one of them, therefore the field is hidden when that country is selected.
If you wish to keep the VAT number field visible, you will have to write a filter for hook wc_aelia_eu_vat_assistant_eu_vat_countries and add Switzerland to the list of EU countries.
Important
Please note that adding Switzerland to the list of EU countries, the VIES service won’t be able to validate a Swiss VAT number. Due to that, the EU VAT Assistant could block the checkout process if the number is returned as “not valid”. To avoid this, you have two options:
1. Enable option “Store invalid VAT numbers” in the plugin settings. That will tell the EU VAT Assistant to accept invalid VAT numbers, without applying an exemption. Please note that, if you enable that option, that will make the EU VAT Assistant accept **any** invalid VAT number, for EU countries as well. It’s currently not possible to accept invalid VAT numbers only for specific countries,
2. Write a filter for hook wc_aelia_euva_eu_vat_number_raw_validation_result and override the result of the validation for Switzerland. For example, you could return “non-eu” when the country is “CH”. Any value entered as a VAT number for Switzerland would be stored as it is, without applying an exemption.
Additional notes
All the above information is provided as a reference. This scenario has not been tested and requires customisations, which fall outside the scope of both our free and premium support services. We strongly recommend to test your customisations thoroughly, before adding them to a live site.
