How to animate a physics-only crash box for the library oldCar?

[woosh]

I made a track where I animate the Old Car from the library - it drives along a road. I would like it to bump into players but the oldCar library node has interaction set to ghost and you can't change it when you link it into your own track, as far as I know. So I thought I'd put an invisible physics-only crash box around it. But I don't know how to make the crash box move together with the old car. In Blender, I can make the crash box a child of the old car proxy and it moves along with it in Blender but not in STK. I can also give it a location and rotation constraintand set it to the old car proxy but again, it only works in Blender, not in STK.
I guess I could copy all the animation keyframes from the old car object to the crash box object but it's a little clumsy in case I want to change the animation later, etc.

What's the best way to do this? Thank you for your answers!

P.S: I use Blender 2.79b so that I can mess with the standard tracks

You need to create your tracking animation in Blender, then bake your animation and you'll have your physical body that will follow the vehicle in Supertuxkart.

Thank you for your answer! Baking the animation almost works except that the crash box lags behind the car
quite a lot. Again, it looks fine in Blender but it lags in STK in the sense that the car and the crash box follow the same path but the crash box is about two lengths of the car behind it. Plus the baked animation looks really ugly on the timeline and in the dopesheet - it's a dense streak of keyframes.

I guess I'll stick with manually copying the keyframes - it works and it's actually less of a hassle than the baking.