My DS takes about an hour to sleep after his 4am feed too. He doesn't really cry though - just makes little grunting noises. So I just put him in the bassinette next to my side of the bed & rock it when the grunting starts. That's usually enough to keep him calm & eventually he falls asleep. (Although it takes an hour, I figure at least I'm still lying in bed & just hanging my arm out to rock the bassinette!!).