Getting the Test Design text into java variable.

I've ploughed thru the code of the CopyUtility. I've changed the ArtifactHandler. I want to read the Test Case design and write it to a file. The testcase I've added the lines:

           Testcase tc = (Testcase)source;  
                // com.ibm.rqm.planning.editor.section.testCaseDesign
            Richtext feature = tc.getComIbmRqmPlanningEditorSectionTestCaseDesign();
            System.out.println(feature.toString() );

But that does not seem to work. Any idea's how I can accomplish this?