The obvious way to plot a path with virtual earth (VEMap.GetDirections) is limited to 25 points. When trying to plot a vehicle's journey this is extremely limiting.
How can I plot a by-road journey of more than 25 points on a virtual earth map?
According to this you need to call VEMap.GetDirections every 25 points until you reach the end of the route and then plot a custom shape of the complete route.