Ka8 Flyer,
Answer to your question.
If you are flying level and you retard the thrust levers to idle,
the FBW system will maintain level flight. Once a minimum safety speed is reached, the autothrust will advance the thrust to prevent the plane from stalling.
I am facinated by the FBW system everytime i fly it. I am new to the Bus and i love it.
Something else that you might like to know:
In a single engine failure, the FBW will keep wings level regardless of thrust settings.
If you lived in Australia I'd take you on a simulator. An experience you can't miss.