hector quadrotor camera change

I am trying to change the camera that comes with the hector_quadrotor_demo that is a front facing camera. I noticed that by using the command "roslaunch hector_quadrotor_demo outdoor_flight_gazebo.launch" the model that loads is the file "quadrotor_hokuyo_utm30lx.urdf.xacro". There, I see a front facing camera. Somewhere in the files I see that there is a downward camera, but when I include the code it never shows up in RViz. The quadrotor_hokuyo_utm30lx.urdf.xacro file has this code: But if I try to include the downward one, exactly as found in quadrotor_downward_cam.urdf.xacro: It doesn't work. I already tried to modify the files, and change the .urdf that is loaded, but no matter what I change, it always loads the same configurations. I also did catkin_make in the ~/catkin_ws directory, and nothing. I am using ros kinetic and gazebo 1.7