How do I use the exchange rate from the PO receipt date and not the PO voucher date?

We are in the process of enabling multicurrency in E1.  I've looked through the knowledge base and many of the community posts but am still unclear on how to use the exchange rate on date of receipt or procurement items and never on date we voucher.

I've update the P4312 processing options > Currency tab > 1. Effective date = Today's Date.  This part is working as expected.

The part which I'm unclear on is how to never see a different exchange rate on the date we voucher.

Any ideas?

Thanks.

Sarah