Struggling to set up the plugin correctly

Hi,
My client only sells electronic downloadable documents as such they don’t have to charge VAT to UK customers, Non-EU customers and any EU customers as long as they can provide a VAT number.

I’ve set up a standard VAT rate of 20% and clicked your button to add all the country codes but what I need is for the checkout to correctly calculate the VAT rate and ask for the VAT number.

Is this possible?

The page I need help with: [log in to see the link]