How to use Arduino Nano as HID with a specific idvendor number and idproduct num

Using Arduino Programming Questions
2

The Arduino Leonardo is ment to act as a USB slave.
http://arduino.cc/en/Main/arduinoBoardLeonardo

For the nano, you could use the V-USB.

I think there is a library to use V-USB with the Arduino. I don't know how to set the idvendor and idproduct, but at least there are many examples for the V-USB.