Contract Purchase Agreement Does Not Default Into Standard Purchase Order Automatically

I want automatically to retrieve prices from different suppliers when creating Purchase orders. I was following How to Create Advanced Price List to Work with Item That Has Two or More Source Suppliers Each with Different Pricing ( Doc ID 2513113.1 ). When I completed all steps there I found that CPA does not default automatically. Then we applied Patch 12625661:R12.PO.B and the feature starts to work when the default supplier currency is the same as Price List currency. However, when I need to change default supplier currency to the Price list currency (when they are different) - the CPA does not default automatically, but if I chose it manually the price from the Price list is retrieved. Please help me to