With the recently posted build of WPILib you should be able to see the AnalogChannel show up on the SmartDashboard in Test mode. From there you'll see the voltages that correspond to distances and it will verify that the sensor is working.
See this page for more information about viewing the Test mode values:
http://wpilib.screenstepslive.com/s/...ode-livewindow
As it shows, you can either explicitly set up the test mode values yourself and get meaningful names for the sensors or you can let WPILib automatically add them. There are examples of each case on that page.
Hope this helps.
Brad