I kinda of solved it, i created an wrapper object (Warenkorb_Item_Wrapper) which holds the actor and added this to the shopping cart list (Warenkorb) instead of the plain actor.
The wrapper has an event dispatcher (bound to a function in the shopping list (Warenkorb) ) which can easily be called from a clicked on item (Warenkorb_Item)
Maybe their is still an easier solution to this?