Nope the volume buttons don't work. The only reference I've found to that is from the description of the "Headset Button" app saying that the iphone volume buttons are not supported by the "Android framework", no more details than that.
There was half a furore a couple of years ago where it was claimed that Apple added a special encrypted chip to the ipods so that they can licence the headphone buttons technology. Result is that the volume buttons can only be used by ipods/iphones... I don't think it was ever confirmed.
I still don't get it though. There has to be some sort of signal that can be detected by the phone when the volume buttons are pressed. Can someone explain how can that be prevented? Or is it a matter of software update Android-side?