We have created a sample of how to do this, including a test program. This is a "first cut", and we may be refining this and incorporating it into a future production release.
Please note that this feature requires use of v4.1.1 beta 1 firmware. It is not compatible with the v4.2.0 firmware.
To use this sample:
1. Make sure you're running the v4.1.1 beta 1 firmware (configured for serial deployment).
2. Open up the UsbHidEchoNetduinoApp project
3. In project settings, select your Netduino's COM port for deployment
4. Make sure your Netduino is plugged in via external power (AC power brick, VIN header, etc.)
5. Deploy the app to your Netduino
6. After the app is running, unplug and reattach the Netduino's USB cable to your PC
7. Windows will discover your "new device" and load the built-in HID drivers
1. Open up the UsbHidEchoConsoleApp project
2. Make sure you've started the Netduino's echo project (above) and reattached your USB cable
3. Run the sample. You'll see it discover and connect to the Netduino...and then send a bunch of echo packets back and forth
This echo sample is unoptimized and is designed to give you a "known good" starting point in using the new USB HID comm channel functionality.
To use the comm channel in your own app, just grab the source files from the two projects and incorporate them into your project. They're licensed via Apache 2.0--so you're free to share the source (or use it guilt free in commercial apps).
Enjoy, and please share your feedback in this thread.
EDIT: updated UsbHidEchoConsoleApp project on 10-March-2011 to fix SafeFileHandle (CloseHandle) issue.