+100 to Felten and Stuster. The cloudiness in a Hefeweizen should be primarily caused by yeast, and raw wheat is inappropriate (save that for Belgian Wits and Lambics). I've had the same experience as you when crash cooling the fermentor before transferring to the keg. My process now is to transfer without crashing.
Some commercial versions achieve reliable cloudiness by filtering the original yeast out and adding back a low flocculating lager yeast for bottle conditioning.
My other tip with Hefeweizen (especially with 3068) is to ferment between 16 and 17C for the initial phase, then let it gradually rise to 20C to finish off after high krausen. I am beginning to come to the conclusion that the typical hefeweizen flavours are driven more by fermentation than mash techniques. My first and many subsequent batches were triple decoctions, however recently I have been experimenting with single infusion with and without a small amount of Melanoidin malt. It hurts to admit that the additional 3 hours spent messing around with a complex decoction mash adds little or nothing to the final result (even using under modified floor malted Bohemian Pilsner malt for the decoction, and premium German Pilsner malt for the single infusion). My first batch with Melaniodin malt is 7 days into fermentation right now, and tasting very promising!
