This document explains how to adjust New Vision prices for taxes. You may add the taxes applicable to your country and their values in the Settings->Taxes window:

Note: when setting prices in the Step 2 of Plan Edit Wizard, enter tax-exclusive prices. New Vision will further calculate the amount to be added to the SUBTOTAL of the user Invoice based on the tax value you set in the window above.

In the customer's Billing->Online Invoice window, taxes will show in the following way:

Note: When you set several taxes, New Vision calculates each of them using the same SUBTOTAL amount, not the resulting tax-inclusive amount. See the following example:

The SUBTOTAL is $14.04, the 15% XYZ tax makes up $1.30, and the 20% VAT tax is calculated using the same $14.04 (XYZ exclusive), making up $2.81.