When the store is based inside the EU and offers 'normal' digital products that do not require any physical intervention (like on-site installation, maintenance or support), value added tax is NOT due for those that download from outside the EU, only for consumers inside EU unless that European buyer has a valid VAT number, in which case no VAT is due either.
If fact, this rule applies for physical as well as digital products and services as far as I understand it -- correct me if I'm wrong...
So what is actually needed is:
1. application of VAT only for buyers inside the EU so the address fields NEED to be there even for digital only cart.
2. exemption of VAT for those EU buyers with a valid (!) VAT number.
This last option is available for WooCommerce as a payed extension for example: http://www.woothemes.com/products/eu-vat-number/ which apparently uses the API http://isvat.appspot.com/ to check VAT number validity. This is important since using false number is illegal and it is the seller that will most likely be charged for the tax after the fact, plus risking a fine...
Any chance of such a feature being created for MarketPress?