Ok - I missed the possibility to associate a tax rule with a tax category. Using tax categories might be easier to configure. I didn't test that with my 4 different tax rules which apply to EU countries yet. In the old example configuration I linked above, you have to assign a tax rule for every product. When using tax categories, you have to assign a tax category to every product in addition to a product category. Using tax categories is 'mandatory', if you are selling digital products in the EU, because you have to apply the VAT rate of the customer's country.