Speed Indication on M56 Nav System ?

[DougC]

Folks, I'd like to have my M56 navigation system show the vehicle speed while driving....I believe that it's more accurate than a car speedometer. I have a Garmin unit on another vehicle and it does this, and it's nice...but I don't seem to be able to push the right buttons to get the M56 nav system to show vehicle speed on the nav map. Anyone know how ? Thanks, Doug