Help supporting WIA for a video driver

I'm trying to get WIA working for a video camera using the AVStream
class (based off of avshws). I have modified my inf according to the
documentation (http://msdn2.microsoft.com/en-us/library/
ms792274.aspx), and the computer see the WIA device, but when I try to
use any of the tools they never get beyond seeing the device.

Using WiaTest, I can select my device in the new device dialog but
when I click ok an error dialog appears. "CreateDevice failed trying
to create a WIA device (The device is offline)". I haven't done any
code to support WIA - are there functions that I need to support? How
do they get called from an AVStream driver?

Thanks,
Matt