MiniDisplayPort to HDMI, Windows XP Bootcamp

Hello,
I recently bought a minidisplayport to hdmi adaptor and it works fine with my hdtv. the problem i have is that i cannot use it when i am running windows through bootcamp. How can i make this work? when i connect the wire while in Windows nothing happens except the fact that i hear the sound that is played when u coonect something on the computer.

I have a late 2010 Macbook pro and Windows XP SP3 installed that i use through bootcamp to play games...