Apple removed the Firewire compatibility - 12V charging support. The new ipods - 5th generation nano, ipod Touch, etc. no longer will charge in older accessories. So far, I have located two adapters which should allow the newer ipods to charge in the older devices - like the Bose Sounddock.
Scosche PassPORT USB Home Charging Adapter ($25.47), Griffin Charge Converter Adapter for All iPods and iPhones ($18.32). I don't think the Griffin device will fit in the Bose Sounddock - it's more for the car accessories. These are both available through Amazon.com. (There appear to be some other options as well.)
Gotta say though - Apple support was awful! I went into the Apple store to ask about this "problem" since I got a nano 5g for Christmas. Do you think they even gave me the explanation of why it wouldn't work? No, their answer was that they didn't make the devices I was talking about (Bose Sounddock, car connection, iHome clock radio) and I would have to contact the manufacturer of each one! I had to search the internet to find out why the nano wouldn't work with the accesories. And why can't Apple make an adapter? They changed the technology. Bottom line - biggest market share, $ matter, not customer support.