i find this way works well...

burn, drill or just tear a new hole in the cap. screw your bowl in. make another hole in the top of the bottle (look at pic, i dont wanna explain it any better than i am) put a tube or w.e u use into it and seal it with w.e. put a tube comming outta the bowl under the cap. put enough water in the bottle so the tube, with the bowl and the cap, is in the water. screw the cap on, put some weed in...and blaze away!