Thank you very very much!
Unfortunately with the child theme it didn’t work, but I solved it by editing the file in the root folder of plugin.
another question, in Cart when i’m going to choose the different free product there is an auto refresh of selection, and i can see the new choice in the shopping list, instead in the checkout this does not happen. it’s possible to make the same function with auto-refresh when i choose the different gift in checkout?
Thank you.