I thought the same, i'm not sure if it's possible.
I tried throwing the ball over the whole thing. That almost works, but it stays left of the goal.
This was my next attempt, doesn't work either:http://FantasticContraption.com/?designId=100195
It could almost work if the ball+motor wouldn't fall down when the big yellow block falls. I hoped they would go over the block...
It looks to me like even if if stayed up there, the best case scenario would be that it'd climb over the yellow brick and the green lines and then fall harmlessly off the map with no chance of reaching the goal. In the current configuration I would guess that it would probably get stuck behind the orange ball after it climbed and fell off the yellow brick.
Its amazing how small the difference is between an easy edit and a thread killer. If the support yellow piece were just a tiny bit shorter, it would fall down when knocked over instead of getting stuck, and the level might be beatable by a 4 or 5 piece machine. As it is, the only viable option looks to be to throw the goal ball with a stick or other ball(s), which would hook on the final green piece, which would swing the goal ball around as it fell and briefly pass into the goal area. Since the machine has to throw almost straight up or throw a large machine, that seems to be a high level of difficulty.