How to enter Conversion rate as user rate at Payment

Summary:

We are seeing an issue with the Corporate Conversion rate for Cross Currency Payments.

Content (please ensure you mask any confidential information):

APAC does foreign currency payments in local currency which are not paid from Oracle Fusion. We get bank statements for these payments in local currency and when we do the cross currency clearing payments, amount is not matching with the bank statement line because rate is different on Oracle clearing payment v/s actual payment made out of APAC bank account.

What can we do to use "User defined" Rates so that we can match the payment with Bank statement.