[petercooper]

Same in the UK, but for instances where you can't get a fully valid invoice, you can either "self invoice" (so the "fill in your own invoice" approach) or just whatever receipt you get as long as you feel happy defending it to a tax inspector later on.

If you use US companies for services in a European business, you are almost certainly going to have invoices every month that don't meet EU regulations at all and you just have to make it work.