In the EU VAT number checking is required and vat numbers must be stated on the invoice when it comes to cross border sales (B2B), aka export of goods and services. A site to check the VAT number is http://ec.europa.eu/taxation_customs/vies/. See my posting in this related thread: http://ofbiz.markmail.org/message/7jtninjzwusf2d37?q=%22German+store+with+vat%22
If, and when, the vat number can't be verified the selling party is required to state the domestic VAT on the export invoice. And when it can be verified the selling party must apply the domestic VAT regime/rules to export invoices, whereby many countries follow the principle to allow 0% due to complications in the VAT collections process (countries don't want to pay other countries) . Start here for a reference: http://europa.eu/youreurope/business/vat-customs/cross-border/index_en.htm The VAT on the purchase invoice has little to do with that, and must be processed according to the country's regulations. Best regards, Pierre Smits ORRTIZ.COM <http://www.orrtiz.com> OFBiz based solutions & services OFBiz Extensions Marketplace http://oem.ofbizci.net/oci-2/
