i had the same prob,
you need to hit the pin that holds the trigger out a bit so the trigger can be removed, i used an old drill bit thet fitted into the hole where the pin is (obviousley hitting the sharp and)
it does take a bit of a whack to get it out so grit your teeth, good idea to take the board out as you do have to hit it hard and the vibes might break or crack the board!
dont take the pin right out, it would be a pain getting it back in!
hope this helps