The tax rate didn't act properly in the cart

Hello!
I have add a tax rate of 0.20!
I chose it in VAT Id in "Product Information" display. Product price (Net) shows 1200, Product price (Gross) shows, as it should be, 1440.
But in cart information Subtotal is 1200, Total is 1200 and Tax Total is 0!
What is the problem?

Thank You and Best Regards!

We do not offer support for VirtueMart, but only for our templates. We don't have much user experience with VM as we are not using it for our projects. We just design templates for it. A good place for VM related questions is forum.virtuemart.net