Thanks, MU65! This got me thinking in the right direction. So for anyone interested or people who might encounter a similar problem, I´ll post my solution here:
I attached an FSM to the object I want to move (my paddle) and gave the action to move my player along the x axis by a global float "PlayerMovement".
Then I made a touch on the left set the float value of "PlayerMovement" to -3 and and a touch on the right screen box to 3.
Then I created children of the two screen boxes and gave them the task to set the float to 0, if they perceive the ending or cancellation of the touch (I used "touch event" for this instead of "touch object event 2d" because that way it doesn´t matter where my finger is when I lifted it).
Phew, this was a tough on (for a newbie like me :-P).
Thanks again, MU65, for priming my pump. I´ve been stuck for a while...