Wilsons Sandbox

Hey all, Just wondering if anyone knows of a good volume control unit that will mount onto my handlebars. Idealy i was looking for something digital that had two buttons on it (up & down)so i could control it without taking my hand off the grips. It would plugin inline between my headphones and my discman. It would also have to be vibration and water proof. I checked out aerostitch but they don't have anything like it, and google has been no help either. Has anyone come up with a good setup on their own? Thanks in advance, Andrew A17C