I have started playing Assassin's Creed Revelations on my PS3 yesterday, and I tried to activate my passport using the code that came with the game. After some loading time, I got a message saying "The service is not available in your country". In in Malta.
At first I thought that may not be able to get a passport at all, so no multiplayer for me. So I tried to get a free 3 day trial just out of curiosity, and it worked, and I have played online for a few hours yesterday. So it seems that passport IS available in my country after all.

So why cannot I redeem the activation code I got with my game?