Copy <EPX>/bin/apps/jspworkitem3WithRODueDate.jsp to <EPX>/bin/apps/jspviewerWithRODueDate.jsp.
Open the file jspviewerWithRODueDate.jsp.
Edit the area between the start tag <USER_WORKITEM_AREA> and the end tag </USER_WORKITEM_AREA> to have your own work item property fields.