Peoplesoft Purchasing Requisition Default UOM

Peoplesoft V9.1, Maintenance Pack 11 & 12, Tools 8.52.16, Bundles through 27

How do I create a "default" Unit of Measure, other than the STD UOM, that will "default" to an adhoc Purchasing Requisition?

Note:  requesters add adhoc Purchasing Requisitions to request items from Inventory (Purchasing>Requisition>Add/Update Requisitions).  The UOM on the Requisition would be the UOM that will be picked, confirmed and shipped from Inventory.   

Scenario:   Requesters need to order the item in the UOM of EA which is not the STD UOM, where EA would automatically default to the Purchasing Requisition when the item is added to the Req line.  

• Item STD UOM is M (M=1000 which is std industry UOM for Forms/Print items)