Disable the iSight in Bootcamp

[Kitty of Doom]

Hello; first of all, sorry for my english.
I'm an Animation student and i need to use a removable webcam in order to put in on a Pencil Test device. In my house I found a Trust 150 Spacecam Portable and, since i found on the official site the winXP drivers and they seem to work fine, i thought of using it for my work.
But now when i open the Pencil Test program it uses the iSight instead of the Trust webcam; furthemore, when i open the application of Trust Webcam, on the bottom there's writter "Apple Built-in iSight" and there's only white where it is supposed to be the picture taken by the camera.
So this is my question: is it possibile to enable the iSight on bootcamp? Or to find a way to make the Trust webcam work? Or it's this one the very problem? (i'm alway skeptical about trust product.. but this one was free :P)

I hope you understood what my problem was; thanks for reading this far