Ahhh, Now you are asking some good questions Ernesto! I am printing from PS CS5.1 and running that PS on an iMac with OS Lion. I've updated the Epson driver with the Lion version of the driver per the Epson site (although I don't know that it is any different from the Snow Leopard driver).
You may have noticed that I reported that the WF1100 prints my 13x19" prints wonderfully. Thus the printing function is generally A-OK.