Sender REST GET adapter renders no xml document

Hi

I have a synchronous REST GET <-> SAP PO 7.31 SP16 <-> SAP scenario where an external party is calling a rest service exposed by PO. When calling the REST service no xml or parameter values are sent as the call is only suppose to trigger the returning of data from SAP.

In PO I need to send the same XML message to SAP every time the REST service is called so I wanted to add an operation mapping to create that xml message to send to SAP. However, I realize that I do not receive any xml from the REST adapter to work on.

Question: How do I configure the REST sender channel to create an xml document that I can use in my mapping?

Kind regards Mikael