How to send XU (Extension Unit) commands to a USB device?

I’m trying to access a VIVE Facial Tracker device. This is a USB device that is basically just a camera that is read by an application to apply facial tracking model to the image.

The problem is that this device stalls if you try to read it (VLC for example). I captured the USB stream on Windows with the manufacturer SDK. I know now that the magic to activate the device is hidden in a bunch of extension unit commands (XU commands) send to the device. I did though not figure out so far how I could send such XU commands using OpenCV.

Both Python and C++ solutions for this problem are fine for me. I just want to make a little program that activates the camera so other applications can start using it.