The simple solution for that would be a special charger with a Y-cable so one can plug the headphones in there when the device is charging. No extra adapters that can be lost. Just include a charger with a y-cable thingie in the iPhone package and they would be done. You buy the phone, you get the new headset with the new connector including a charger that allows to still plug in the headset. If that will not be the case I don't know why Apple cannot think of such a simple solution.