It is generally considered bad form to ask how a professional magician (on TV or otherwise) does his magic. It is also considered bad form to tell.
While I haven't seen the episode in question, based on what I think it is from your description, it is a standard stage illusion that any experienced magician would know. If you do not know it, then (and I say this trying to help, not insult) may I suggest taking some more time to round out your foundation in illusions before trying to attempt it.
Like so many things Angel does, your venue will not be nearly the same as his. The trick demands quite a bit when it comes to staging it properly. Interesting, most magicians who do the trick today leave out two wonderful touches that really do make a difference.
The trick is well over one hundred years old, and most entry level illusion books will discuss it. While it is not in Wels's Great Illusions of Magic, that is a good starting point for someone wanting to learn illusions. In fact, all the principles can be found in that two volume set.
Brad Henderson