Honestly, is there a reason you have to stop formula at 1 yr? Just because the doctors say? At 1, I think they still need the calcium and such that comes from formula, especially if you are not planning on giving him milk. Of course, the concern would be more of him going to sleep with formula on his teeth. Perhaps gradually weaning him from it would be best, making the night time bottle the last, then just put less and less in the bottle over a period of a few weeks. Then you might try just water (never juice), until you just rock him for a few minutes.
Personally by this age, rocking for a few minutes is good, but it should not be until the child is completely asleep, then when you get to a time when you would like your child to just go to bed and sleep, he will not be able to fall asleep on his own. Had a friend whose daughter was over 4 and she was spending over an hour every night rocking her to sleep.
Perhaps gradually forming a new routine of reading a book, and a few minutes of rocking, then putting him down to bed while sleepy but not asleep. So he can learn how to fall asleep on his own. He will become a better sleeper and you will keep your sanity.