Can You Still Play Demos from the Playstation Store After the Game Has Been Released?

So I downloaded Battlefield: Bad Company 2 Multiplayer Demo on the online store and tried to play it. I selected Play Now and it was connecting. After about 10 seconds it says it was 'unable to connect to EA servers.' There is nothing wrong with my internet connection as I could play GTA IV online, download from the Playstation Store etc. So I was just wondering, since the full game has already been released, is the demo not supported anymore for online play? If it is, are there any suggestions as to how I can get it to work?

Suggestion:

If its an online BETA demo then after the game is released, you can't play it anymore as the online facility/service is needed for the actual game. however if it's an offline game (where you only play storyline, etc) then it is fine and you can play it forever.

i know this because i have experienced it. for example, i downloaded uncharted 2 online demo and when the game was released i couldn't play it anymore however i can still play the original uncharted game demo that was only storyline and didn't have the online bit.