Nope, this didn't work. I downloaded the Ep3 files, cleared the temp directory, and ran the game and selected get. It immediately told me there was a connection failure. Tried it 5 more times, same problem. Re-deleted the temp folder -- re-did all the other steps -- no dice.
Now apparently on top of it all, my savegames are gone. I'll restore from the backup, but I have a sick feeling that I've just plunked down my hard-earned money for only 2 episodes.