Hey rex, awesome behavior, but I don't understand something. I downloaded the capx, but where do you associate the spline with the waypoints? I mean the actual Waypoint object, I can't find where do you say "hey use these waypoints for the spline". I mean there is the Add point action but it's not being used in your example. I'm scratching my head here.
EDIT
Found it, I just needed to expand the build path function. Can't delete the post for some reason.