You have a USD / CNY invoice that needs to be paid, and we are paying this from an AUD bank account. The amount you will pay from the Bank will approximate the F/C rate, but won't be exact due to charges / rounding etc. (hence we don't use the exchange rate)
On the Payment screen, pay the F/C invoice as normal, in my example, I've paid the full amount, CNY1048777.45 against the invoice.
My bank has advised that this will cost AUD$300,000, not the AUD$214036.22 which was what the invoice was originally booked in at.
I enter $300,000 in the Local Currency
I don't click on 'Calc', as that would overwrite my AUD amount.
I click on Post
In the GL my transactions are:-
Creditors has been credited AUD$214036.22, clearing the AUD value of the invoice.
Bank account has been debited AUD$300,000, which was the amount I actually paid.
The difference of $85k goes to Exchange gain / loss.
It's important to remember that you are using Minder as 'Multi-currency', so all accounting is referenced back to AUD and the F/C amounts don't have any financial impact on your GL. The amount owed to a creditor will always be AUD. The F/C amount is simply carried with the invoice details.