MS Lifecam API / Webcam Button

Question

I have a Microsoft Lifecam Cinema webcam. I'm using directshow to get a feed and take pictures from the camera, however I want to use the button on top of the camera as a capture button.
Is there any way at all I could access this button using directshow? The camera also comes with an API, but I don't really know how to use it, and its undocumented. Perhaps somewhere among the methods is something that allows me code against the button?