It is soooooo common for (especially boys) to not be poop trained for long after going in the potty. They sometimes have fear about doing it, or it doesn't make sense to them.... I have NEVER met a guy in college who still pooped in his pants, so don't worry, it will happen. Let him unfold as he will, and don't take his lovey from him when he has an accident. I would try bribery first. My daughter loved stickers, and I offered her a sticker to put on her potty every time she went to the bathroom...or a gummy fruit thing. I would always remind her that the option was there, and she knew it was....but honestly, just one day she just started doing it, and she hasn't had accidents since. I have heard this to be common. There really isn't much need to "train", just trust he'll get it if you keep making it available. SOmetimes if they think you are upset with them when they go in their pants, they try to hold it, but that causes the reverse problem, that they end up going in their pants because they are holding it too long. I've also heard of kids who just don't want to miss out on anything in life, and don't want to spend the time on the potty! :)
Anyway, don't worry, your child will get it, in his time and in his way. We need to leave room for our kids to just develop the way they need to. I read a great article from "Lifeways" yesterday that spoke about how, if we remove ourselves from the "behaviour" that we can see actually how what the child is doing is part of their temperment, part of their own individual way of existing in this world. The author used the example of her daughter, who refused to walk except holding someone's hand until she was much older than "normal" walking age. Friends kept telling her that she should be "evaluated" and worried. One day, her daughter was in the middle of a room filled with people, and she just got up, and walked 16 steps. She never did the first two steps, never geared up for it, just thought about, and then did it in her own time. She then goes on to write that throughout her daughter's life she saw this part of her persona play itself out, and that it is a benefit to her in so many ways.
So...that may not tell you how to "train" your kid, but hopefully that encourages you that it is just a season, and it will happen. Unfortunately, you may have to clean up poop for a little bit longer, but I would love to hear how you view all of this in a year, when all is well!
R.