Transfer purchase order to another system using PI

Hi expert,

I need to transfer all the purchase orders by IDOC to another non SAP system using PI. Can anybody tell me how to do it? What is the transaction to collect all the purchase orders and create the IDOCs? I know for vendor master data, we have transaction code BD14 to do it. And then we14 can process them. Do we have the same for purchase orders?

Thanks,

Charles