How to add rqt_robot_steering parameters

edit

Hello guys, My environment simulation contains a Willow Garage and a pioneer3at. I see that by rqt_gui (precisely by rqt_robot_steering) I can manipulate parameters as linear velocity and angular velocity of pioneer. In fact the code of rqt_robot_steering.launch is:

<launch>

<node pkg="rqt_robot_steering" type="rqt_robot_steering" name="Pioneer3AT_rqt_teleop">
  <param name="default_topic" type="str" value="/Pioneer3AT/rqt/cmd_vel" />
  <param name="default_vx_max" type="double" value="0.8" />
  <param name="default_vx_min" type="double" value="-0.8" />
  <param name="default_vw_max" type="double" value="1.5" />
  <param name="default_vw_min" type="double" value="-1.5" />
</node>

</launch>

If I would to manipulate parameters as linear velocity of a single wheel, or apply joint effort or apply body wrench, implementing them on rqt_robot_steering.launch, how can I edit this file? Thnx