(I do know the structure of the packet the USB receives, so I am looking for something similar to that).
What ever you are looking for it is not that.
At the moment I have a touch screen that I usually interface to via Windows (serial DB9 RS232 connection).
It would be good if you provide a link to it.
To convert RS232 to something you can feed into an Arduino you need a level converter something like the Max202 or one of the very many variants.