Taxes on purchase and not on sale

[cobra-arbok]

I'm new to VirtueMart. I just installed the latest version in Joomla (latest version) and I'm doing some testing.

I already have this first problem.
Product A is purchased at €100,00 with 22% VAT, but is sold with 0% VAT. (Taxation in Italy for a certain type of sale)
Therefore, the calculation will be:
Sale price = €100+VAT22%+Trading Margin+VAT 0%
How do I enter this rule?
Thanks in advance.