Hi Pavithra,
I am slightly confused when you mention about the temp GUID.
I agree that would happen when you create a new PO however, the reference PO that you would use would have a GUID which you can pass to the CRMD item table to fetch the values already present in the BE_UNLOAD.
Can you confirm if you are able to fetch the values maintained in the existing PO's.
Br,
Raghu