How are you doing the transformation? Do you have an XQuery and you replace body? You should be able to see this from the OSB Console.
If you want to make it easier, you can use the Log action after the transformation, logging $body and setting the loglevel as error. Then you will see the payload in the weblogic log file.
Or assign the transformation to another variable, just for testing purposes, you will be able to find it easily in the OSB console.