Currency rate in Standard PO should be on PO creation date not from Contract

Hello all!

We need that in Standard PO that is automatically created from catalog requisition (related to CPA or BPA) the currency rate should be taken "Corporate" on PO Creation Date, not on Requisition.

Currently when requisition is related to CPA or local BPA - the rate is taken from the Contract.

If we create global BPA and create requisition related to global BPA - then in requisition the rate is taken 'Corporate' on requisition creation date, but as approval of requisition can take some time, PO can be created in several days and the rate will be taken from Requisition, but we need that the rate in PO will be taken on PO creation date and PO must be created automatically by Workflow.