Prestashop currency converting problem in PAYPAL

[jfd]

Hello,

I run a prestashop in which I sell a product in two currencies: EUR (main currency) and USD.

Same product costs 10 EUR and 18 USD. Exchange rate is set manually to 1.80.

Problem occurs when customer from USA wants to buy a product which in my shop is for 18$ and when paying via PAYPAL it converts it automatically to 13 EUR.
I cannot set main currency in paypal to USD because then european users who buy in EUR have their currency converted to USD in PAYPAL.

What should I do to resolve this problem?
 

Thank you,

John