When CBSubs tax plugin is installed, and tax rate configured to use EU VAT as VAT number validation, then as soon as user types-in a company name in the invoicing address, and selects an EU country, then a "EU VAT" field appears (instead of the Tax numberVAT field that appears for other countries and when EU VAT is not set properly.
Then when user saves his invoicing address, the EU number is validated, and if the number is validated at EU tax services, then the corresponding B2B tax rate is applied, typically if there is no B2B tax rate (e.g. your EU VAT tax rate is configured for "Export: B2C only") and you don't have other tax rates, then no tax will be counted for the B2B intra-EU export sale.
(in EU you would typically make invoicing address mandatory in general settings).
Pages 281-288 of CBSubs 1.1.1 manual explain the settings:
For EU tax (for most companies, but check with your accountant/tax advisor first of course), you need a CBSubs tax rate that applies to your "sales" tax rule to be created and set as sole default for your sales:
To Buyers in: European Union
From: Sellers anywhere (in your case, that would mean automatically your EU country)
For all domestic sales
For export sales only B2C
Validation for Business ( B2B ) condition: EU VAT Online, check with EU VAT Server
That way, domestic buyers get taxed, as well as customers in other EU countries, but no export businesses, and not customers outside EU.
EU tax rules are complex.... E.g. if you make over a certain amount of export sales into another EU country, you can/must (check with your tax advisor) get another EU tax number for that country and invoice (and pay) the country's own tax rate for all buyers in that country.
CBSubs's Tax plugin allows such complex, and even much more complex tax rules for internationally active businesses in any country.
Let us know if the above helped, if not, we will make a more detailed description and can help you configure your taxes on your CBSubs installation.
Edited typo
Post edited by: beat, at: 2010/12/21 14:19
Post edited by: beat, at: 2010/12/21 14:20
Post edited by: beat, at: 2010/12/21 14:21