ingsan:
I hope that I am understanding your question correctly.
(in the ball actor)
Try adding a "collision event" --> add action "physical response" to "flipper1" and then another "collision event" --> add action "physical response" to flipper2" in order to get the ball to bounce off the paddles.
You may need to script the ball physics to make it more realistic but this should get you started.
I haven't tried this out in exactly your situation but I think it will work.