during phone call on the mac via FaceTime

Hi all,
I often use my mac to make phone calls. I call my bank, and my bank uses a automated voice messaging system where I have to enter in a number on the dial pad to make a selection. Often times, I have to enter in my debit number via the dial pad. When I tried typing the numbers in FaceTime, nothing was being passed through. How do I dial numbers on the dial pad to use with such services?