Credit Memo need to inherit the currency convertion date from the related invoice in Peru

Summary:

Credit Memo need to inherit the currency convertion date from the related invoice in Peru
It is required that the credit memo inherit automatically the conversion rate from the related invoice inclusive in documents that are in PEN due to the primary book is in USD

The currency of primary ledger is USD
When we create an invoice in the accounts payable module in PEN Sol Peruano, an exchange rate is used in foreign currency.
The business need is to create a CREDIT MEMO related to the invoice and for the exchange rate of the related invoice to be retrieved AUTOMATICALLY