Hi sschiu,
Thank you for the information. I have called the school who said the letter is not required at the time of application but I would have to present it when they start to process the application at later stage.
Yes I don't want to disclose to current school. That is why I can't get the reference letter, not even when we get the chance to interview! The current school may refuse to write it and get to know our application to another school!