All you can really do is continue offering it to him, eventually he'll be hungry enough to take it. Have your husband or someone other then you do it to start out though, if it's you he's going to want the breast cause he knows YOU HAVE IT. Also try different bottles and nipples sometimes it may just be he doesn't like the one you're offering.
when i tried that with my oldest...it was VERY hard to do...i would let her suck on just the nipple of the bottles by itself untill she got use to that ( i didn't use pacifiers) and then when i would gradually sneak the bottle in..in place of myself. It was tricky, but if your baby is really having a problem with it this may work for you.
R u switching from breastfeeding. If so I found with both my kids that the playtex nursers worked the best to transistion from breast to bottle. I had to experiment with different nipples til I found one that they would like.
I switched my baby from breastmilk to bottle when he was 4 moths old. I was hosptialized and given meds, so I could not feed him anymore. He did not have any problems switching. Once I was released from the hospital though, he did want breastmilk whenever I gave him the bottle. So, what we did was have my husand feed him. When he was not here to feed my baby... then I would do it wearing one of my hubby's shirts.