415 Unsupported Media Type while testing POSTing to REST Service

I'm attempting to use SoapUI Pro to test my REST service running inside of Mule ESB on my local machine.  I have created a new project in the tool.  I then created a new REST Service in my project, set the other required data (endpoint, etc.)for the service.  I've also made sure to select POST, selected text/xml for Media Type and have entered valid XML that I'm trying to POST to my service.  I've verified that the request is being received by Mule.  However, the headers returned show the Content-Type as text/plain with a content length of 0:

 

So, my question is why does it seem that the media type is being ignored and that my XML is not being transmitted.  I'm running the 2.5.1 pro version.  Any ideas?