I am trying to route a message based on information in a XML snippet stored as a local entry (key=mapping_id_ep_v1.xml). The id used to look-up the correct endpoint and it
I have got a similar situation. The problem seems to be that you cannot perform xpath expressions over a property content.
You can easily do what you need by using a Javascript script after loading the xml into a property. Javascript+e4x offers an easy way to access to XML content of variables by xpath expressions.