During ATP check, can "special" stock be confirmed against incoming Purchase Orders?

During ATP check, can "special" stock be confirmed against incoming Purchase Orders?

Customer has ordered an MTO part that we are ordering from our supplier. The PO item with arrive 1 month from today.

Even though the scope of check is set to consider POs, the PO isn't showing in ATP overview (w/ checking rule "AE") and the user can't confirm based on this incoming quantity.

Please advise. Thanks.