Full documentation can be found at 2Virt.
2Virt Devices are meant to be a special type of USB devices that offer USB interfaces for accessing different services of the Virtualization platform.
Different 2Virt Interfaces can be used for adding the to a USB device, that a client program, running in a Hardware Virtual Machine can use to take control of platform services, even from priviledged domains.
softusbproxy directory contains the implementation of the COM objects which simulates a USB bulk device using Microsoft's Device Simulation Framework (DSF)
You will need to install Windows Driver Kit in order to install DSF.
Once compiled you will need to register the resulted COM object to the system. Run regsvr32 SoftUSBProxy.dll as an administrator.
You can simulate the plug-in of a such device on your machine using the RunUSBProxy.wsf VBscript: cscript.exe RunUSBProxy.wsf
The device is described by the following: VendorID=02A0 ProductID=A123
usb2virt directory contains the sources for a USB device driver implementing a Bulk interface.
If you add the device using DSF framework and COM device implementation you will notice you will be prompted for a device driver. You will need to locate the compiled usb2virt.sys file which will load the device's functionality.
Box2Virt directory contains a C# app that will use the device files exposed by usb2virt driver to issue IOCTLs and read/write to comunicate with the device.