How do you get Shivering Isles

If you have the expansion pack you need to start a new game.When you ecscape the prison a note will pop up and say strange door has opened on Nibey Basin by Bravil.Swim to the island and a big statue of three heads are there.A gaurd will be there.Talk to him.then a voice from the head says a few things.Walk into the mouth of the head and a man (forgot his name)tells you to sit down.He says a few things and then the room disappears and you are in the Shivering Isles?!