Unlikely: Portuguese Media Reporting Text Messages from Plane
The answer is, they can't. 900/1900 MHz cell phone signals at 0.6 watts aren't going to make it more than 5-10 miles, or so. Only possibility is if this A330 was equipped with some new system to permit mobile phone use in flight. Such a system would pick up mobile phone signals from inside the airplane, then retransmit them on some long-distance-capable frequency (perhaps via satellite) to some land location for re-injection into the public cell phone network.