Dear Fabrizio, when you mention any kick with Ossaya, it means that kick is going to hit from back. But, you are explaining that you bring the back leg to the front like Yad Keyeto. That is why I don't get it.
If the kick hitting with sole of the foot, it should be a Horaiyma Keyeto. Or, hitting with top of the foot or heel, should be Sima Keyeto.
Is the kick you are asking in the classical lesson?