Just want to share some experience with u. My Sky was used the milk bottle after 6 months old. I think the most important thing is to be hard-hearted!
During that time, my Sky was refuse to drink milk & keep crying... few hours later he 'force' to take milk bottle as he knows if he don't take then he will keep hungry. Of course you have to hide urself too... Let ur hubby (I think is the best person) or someone to feed him. After 1 & 1/2 days, he eager to take it even I feed him by using milk bottle.