Controlling the lights on a XPS Laptop

Hi, I know there is the Quickset utility to control the lights on the XPS laptops. What I would like to do is put together a DotNet app to access the lights. I have found a couple of references on the Internet which seem to indicate that there should be a C++ dll around which a DotNet wrapper could be written. Does anybody know what this dll is called, where I can find it, and whether there is any documentation on the API. Thanks