Hello Cavo,
for me tax is working well now - in the way that i wrote you via PM.
i have mapped all fields from registration to the invoice-adress (done in the invoice settings) but not the country!
so the invoice-adress is always "open" the costumer has to choose country again and click save-button - only in this moment the tax will work
if the costumer buys again then the invoice-adress is already saved into database - you have the problem again - i solved it with an auto-action which is deleting the field and so the invoice-adress is always open the country is never filled and the tax is working
and yes you need 27 geographic-regions, 27 tax rates and the tax rule EU VAT B2C
but for me the promotions are still not working