I have IBS and I'm lactose intolerant too. I tried Lactaid when it first came out and didn't have any luck with it. They do, however, have a lactose free milk. I have not tried it, but you might consider that, if the Lactaid doesn't work for you.
So it seems as though the lactaid does not work. I have tried the soy milk and I really wanted to like it but it just does not taste like milk to me at all. I might try lactaid just to see because I just love the taste of milk. Sometimes I drink it even if it will make me sick it's just so good.
My friend is lactose intolerant, and the lactaid does help her. However, if she eats something with a lot of dairy, like ice cream, it doesn't help as much. she is not a big milk drinker, but i would imagine that the milk would have the same effect as the ice cream on her. so, yes it does help for certain things, but maybe not so much on your milk :-( you should try it for yourself anyway because it might work for you. good luck!!