a quick update:
the VAT invoice I got is totally useless (and actually it makes no sense).
In fact under the EU VAT law governing the sale of digital goods “a business must alway charge VAT to non-VAT registered entities (ie. consumers) but should not charge VAT to foreign EU VAT registerered businesses who provide them with a VAT number. These foreign EU businesses are required to declare their purchase and the tax due to their own tax authorities.”
So a VAT invoice from iTunes Sarl to me (with my Italian VAT number) and 15% (Luxembourg) VAT charged is definitely incorrect. I’ll wait and see if I can get a refund for the VAT I paid and then a proper invoice.
So yes, you’re right. The Apple Store is not ready for European professionals (unless they’re based in Luxembourg).
And I think the Business Store representatives don’t know anything about VAT invoices for apps because we’re not buying from the Apple Store but from iTunes. Apple Store has a legal rep for tax purposes in Italy, and that’s why they charge (correctly) 20% (Italian) VAT.