Stay up later to catch them in the morning or go to bed earlier so you can wake up in time; these are the easiest solutions.

Going to bed between 4 to 6 am is fine for developers... but not for business men.

As you enter the business world, you will have to readjust your schedule to be in synch with the rest of the world. Trust me, as you are selling products and especially when you start dealing with customer support, it will be extremely convinient to start revolving your life around "normal" business hours.