Audio out USB port??

[JINXR65]

I currently have a custom dock on my dash for my HTC Hero (CDMA) and it has the HTC proprietary mini-USB with extra pins for audio. I'm wanting to get the Optimus S, but I really want to keep this feature. I know the Optimus uses the micro-USB, so I realize I will have to modify my dock, but is it possible to get audio out of it? I really don't want to have to plug in a patch cable to the 3.5 jack anytime I want to run the audio through the speakers.