Don,
The link below takes you to Van's picture of the towbar.
http://www.vansaircraft.com/cgi-bin...987-96-144&browse=airframe&product=12-tow_bar
This picture is with the legs in the retracted position and rotated through 90 degrees, so this is the configuration for use as a brake/rudder lock. The handles rest against the seat bulkhead under the curve of the pilots stick.
The other ends sit on the rudder pedals with the "turned up" ends pressing against the brake pedals. The instructions explain how to set up the legs and drill a hole in each so that they are the correct length to apply pressure to the brakes.
It only takes a few seconds to reconfigure the tow bar for manoeuvring the aircraft on the ground. The black band near the handles is a velcro strap which ensures the ends cannot jump out of the axle while pulling/pushing. Seems to work just fine.
Cheers...Keith