This is the charger/bypass I was using my factory HU to charge my iPhone 3G (Scion Pioneer Audio is FireWire based apparently), so I purchased this, and an ipod extension cable from http://www.cablejive.com/ (who are also working on a charging converter just like the kensington unit is), and now I have a 6ft longer iPod cable, and it charges my iPhone 3G, all works just like factory.
I use this with my new D3 as well, so I can confirm it does work, and greatly reccomend the charger for a simple fix, also, check for it on amazon, I scored it there for 15$, it's 30 from kensington..