Adding a JSON string to an outbound RESTful call in OSB 11.1.1.6

Question

Inside my Proxy Service Message Flow (OSB 11.1.1.6) I have generated a JSON string and stored it in a variable named $jsonReq.
In my Routing action, I point to a Business Service whose Service Type is "Messaging Service" with both Request/Response Message Types as "Text".
What is the proper way to assign the $jsonReq variable's contents to the outbound request body (I am doing a POST)?
I have tried a number of configurations, but to no avail (though I see the JSON contents when I dump it out in a Log action), such as:
Insert
Expression: $jsonReq
Location: as first child of
XPath: .
In Variable: outbound
Please advise.
Thank you,
Michael

Answer 1

Hello Prabu,
Thank you for the suggestion. Assigning it to the body didn't work. I changed my configuration to this:
Insert
Expression: $jsonReq
Location: as first child of
XPath: .
In Variable: outbound
The net effect that I can see via the Test Console invocation tracing is that the change from:
RouteToMyBusinessService -> Message Context Changes -> changed $body
<soap:Body xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
<!-- our original body from the proxy service inbound SOAP message -->
</soap:Body>
to
RouteToMyBusinessService -> Message Context Changes -> changed $body
<soap:Body xmlns:soap="http://www.w3.org/2003/05/soap-envelope"/>
I know that the $jsonReq has data in it (per a log statement I made: <Jun 6, 2013 7:55:40 AM CDT> <Debug> <ALSB Logging> <BEA-000000> < [RouteToSCCreateBAMLabsProfileBusSvc, null, null, REQUEST] Inserted {"firstName":"string","lastName":"s","email":"stringstring","Login":"string","timeZone":"America/Montevideo","address":{"streetOne":"string","streetTwo":"string","city":"string","state":"st","zipCode":"string","country":"string"},"equipment":{"e":{"type":"Bed","code":"string","serial":"string","sku":"string","version":"string","dateOfPurchase":"2013-11-23T08:44:07"}}} into body> ).
So why would the body be empty when I use the Insert action listed above?
On a side note, is there only one 'body' variable in a proxy message flow? How do I distinguish between the body of the incoming request, the body of the [transformed] outgoing business service request, the body of the business service response and the body of the [transformed] proxy service response?
Thanks again,
Michael