it's not easy..I've tried in the past with cylinders using cloud textures, but it wasn't too convincing..;) If you're up to it, you might try making a greyscale image of the wake, then import it into Bryce, and make a water texture..spray..now that's hard..

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)