Need to default Product Category on iProcurement requisitions and Buyer Work Center purchase orders.

Hello -

We are in the process of changing our eBtax rules.  We are going to use product category and intended use as the main drivers for our rules.  We would like to (behind the scenes) default the product category on the iProcurement requisition and on the Buyer Work Center purchase order based on the purchasing category value.  We are trying to reduce the information that the users need to enter.  We have created a DFF segment on the purchasing category to hold the corresponding product category.  Our original thought is that we would need to perform OAF extensions to obtain the