First off, if your horse can't lunge, that's kind of bad. Horses don't have to know how to lunge, I know plenty of good ones that don't, but I personally have found that numerous exercises, like Spyder said, can really help a green horse figure things out. I'm a firm believer in letting the horse figure things out for himself instead of me telling him or forcing him into everything. It's like raising a child.
I would say, pick up a nice canter, do two circles and the go over a pole. Don't change anything. I will bet money that one of the biggest problems your having is that you now expect him to run over fences and your are unconsciously telling him to with your body. I know you don't mean to, but the key is to stay the same. Jumping a pole, a 2 foot fence and a 4 foot fence should be equally calm.
How is he over a single pole? Or two or three? If he can't do those calmly, do not expect him to jump calmly. What kind of boots do you put of your horse when you jump? For some horses, I like the open front splint boots because it stings a little if they hit the pole but their legs are still protected. I would definitely say use them, regardless of what kind, when you are jumping because if he has a habit of knocking down fences, he can injure himself.