Message on iPhone but not on MAC
I have a MACBook Pro and and iPhone 4s both with the app messages. Generally a message appears on both and I can send from either. Yet the other day I was given a phone number and tried to send a message via my MAC but it was unable. Yet I successfully sent a message to this person via my iPhone and he responded. The bubble on my message was green not blue, so I assume my message did not go via iMessage. Is there a way how I can make his name appear in my MACs messages so I can send him future messages from my MAC? All I have is his phone number.
MacBook Pro, OS X Mountain Lion (10.8.2)