AP holds approval in BPM for PO matched invoices

Summary:

We want to configure the BPM to route the PO matched approval to the requestor provided in the PO.

I have configured the IF conditions the following:
FinApHoldApprovalPayloadType.holdName in "amount ordered", "price", "ordered quantity" and
Invoice Line.Requestor Name isn't null and
Invoice Header.PO Number isn't null

I think this should be correct, however I am not sure how the THEN condition should be set to derive the requestor on the PO.

I have tested supervisory with participant: HierarchyBuilder.getPrincipal(Invoice Line.Requester Name,-1,"2026-01-01","null")

I have also tested resource but the expression builder is not available under user.