If you are dealing with customer, you need to create and link the trade receivable (customer) of the respective currency as well.
1. First you have to create the account (Trade Payable or Trade Receivable) at Account Module- ACCOUNT LIST
2. Refer to your account list and decide next account number. Click on the NEW to create new account.
4. To create a TRADE RECEIVABLE account for foreign currency (Eg: Trade Receivable Euro), ACCOUNT TYPE select ACCOUNTS RECEIVABLE, then enter the account number and account name.
5. At the account DETAILS, change the currency to respective currency
6. Select OK when system asks permission to create and link the exchange account for user.
7. Select OK after exchange account is created and linked.