I'm trying to use a USB video capture device in a flash based video chat, but
the flash player AVPresence does not find video4linux USB devices. It finds
other PCI capture devices, but does not work with the USB ones.

I'm not sure if the AVPresence code looks for existing /dev/video* devices or
looks at the loaded modules, but if somene can tell me where/how to look a the
code for AVPresence, I can probbaly fix it.