4 year old boy only poops in underware...always has!

My 4 year old son who has recently started school, still will not go to the toilet to do his stools. Infact he never has! He has no problems with going to the toilet to pee and never has accidents with that area. Over the last year I've consulted with his GP who refered me to his Health Visitor, (who really didn't seem much help at all). He was refered to a constipation clinic to make sure he wasn't constipated. They recommended that he was to take Movacol just to make sure that he could pass stools easily. He was then refered to a Childrens Clinic where we discussed many stratagies, and ideas to encourage him to go to the toilet. However, NOTHING has worked. (From sticker charts, to completely ignoring the situation.) He was then refered back to his Health Visitor, (which I was really unhappy about as we had no joy the first time round!). So recently we have been dealing with child psycotherapy. As, at the moment we are trying to use the "ignoring the issue" stratagy, only me and my husband are attending the sessions with the Psycologist.
It has kind of helped me to cope with the upsets of it all. But we still have no answers!
I'm so desperate to help my son, as the other children at school are starting to notice who is making the nasty smells in the classroom. I'm frightened that he's going to be bullied.
And I just don't know what the hell to do next.
Thank you for reading.

[TJ71]

Any one? Please don't tell me I'm on my own?

[Trev673]

I also have a four year old son who always has pooping accidents.   It is frustrating b/c he always pees on the potty.  If you find a solution ley me know good luck.

[cmr333]

I have a 4 year old son that will pee in a toilet with no problem, but for the past year he will not go poop in the toilet, he will sit on the floor and hold it in and rock back and forth til he doesnt have the urge to go anymore, and eventually he will hold it for so long it will leak out into his underwear.  The doctor said he was really constipated.
I started with giving him clear fiber drinks, just in a lower dosage. I was using a Poop Chart, and everytime he would poop in the toilet, we would put a sticker on the chart and if he goes a whole month with no accidents and poops in the toilet once a day then he will get to go somewhere special.  That seems to be working really well. Then the doctor introduced this disease called incopresis to me. It is very common in toddler boys.  http://www.kidshealth.org/parent/general/sick/encopresis.html this is a link that will explain it to you a little better.
What i did when i read this and realized this is exactly what he has, i began to try many different things, one was explaining to him that his body makes poop and when the body is done making poop everyday it wants to come out and into the toilet. and that is where he has to come in and help his poop come out everyday. i know that it sounds silly, but it actually worked, and encouraging him to sit on the toilet about 10 minutes after he eats helps too.
In my sons case, it was hurting him to go to poop, so he was just holding it in, so i started giving him fiber drinks and fiber bars and that helped soften his stools.
He is doing much better now, and i dont see him holding it back that often, i make it like a game for him and that way he see's that it is not a bad thing.
let me know if you have any questions