I did a bit of searching over at the xda-developers forum(
xda-developers - Powered by vBulletin) and it looks like VC might not work with a wired head set. Is Bluetooth an option for you? I did find one thread where somebody wrote a little application to make a wired headset work, but it was device specific and may or may not work on your device
New application: Talk Button Detector 0.3 - xda-developers Not that only registered users can see attachments.