If your data structure is coming thru from the WSDL properly, then you would double click the _jsx_null_jsx_ line or it should parse to your data structure. But based on that name for the output response, I would guess its not getting a properly parsed WSDL from your source.
Do you get any kind of message if you double click that line? Have you clicked the "Ru;le Node Profile" radio button below the Rules Tree window while the _jsx_null_jsx_ line is selected, that will tell you what it sees as comprising that line.
The response line should be mapped to a CDF Document name, the Result line should contain CDF Record as your mapping type, and the _jsx_null_jsx_ line/section is where your data structure should show up when its properly parsed. But showing a "_jsx_null_jsx_" would lead me to believe there is something wrong there, have never seen a WSDL parse to something like that.