What's the problem?
EDIT:
1) Install the VA software
2) Make sure your mike is working as an input device
3) Run the Windows voice recognition training software at least 3 times (the more the better)
4) Go into VA and make a new profile
5) Add new commands. Each command can be bound to keystrokes, invoke sounds, etc etc.
6) Don't make the commands too long, or too similar.
You might find VA occasionally stops working or gets erratic and doesn't recognise some commands. If so, stop it and start it again. No need to reboot the game itself.