I have a customer in Thailand who is sending a trial order. He wants to make a payment but wishes to pay in US dollars. However, we don't deal in US dollars, only in our local currency. My boss said that we can accept US dollars, but the exchange rate will be based on the amount received in our local currency. How can I explain to him that he can make the payment in US dollars, but the exchange rate will be based on the conversion from US dollars to our local currency?