The source of the XML node to be stored. The source can be a 1. Property 2. XPath Expression 3. SOAP Envelope 4. SOAP Body
If clone is true a clone will be create and stored from the origincal content. Otherwise a reference will be stored.
In case of property a OMElement is stored in a property and it will be fetched.
In case of a XPath expression, it will be evaluated to get the OMElement
In case of SOAPEnvelope entire SOAP envelope will be stored
In case of Body, the first child of body will be stored