Depends on who you look to for spiritual guidance as to "how" you take refuge in them.
I do agree unless you "take refuge" in them, then you probably can't really consider yourself a buddhist.
Ceremonially there are many ways to take refuge. It can be traditional or it can be private (as in my case).
One day I am formally and publically take the vows, but I don't really feel the need to at this point.
BTW, the vows do not require you to denounce anything you believe in. Only to accept the teachings and the path.