Validating VAT numbers for EU VAT registered customers

We currently run an in-house built ecommerce platform that we would like to replace with a hosted solution (Shopify, Volusion, BluePark, etc) for reasons of support & features. At the moment, for a non-web design company, we spend far too much time on website development! Our in-house system allows EU VAT registered companies to enter their VAT number and if it is valid (we automatically check against VIES), VAT is not charged.

I am struggling to find any hosted ecommerce platform that supports this and would love to hear from anyone who has a similar requirement and what you do.