If you don't want to wait for the feature:
If you make toggle on the "everything off" position, you could set a command to start when you press the button containing:
Stop VoiceAttack listening
Disable Hotkeys
Start Loop While : [{STATE_JOYSTICK1BUTTON:1}] Equals '1'
End Loop
Start VoiceAttack listening
Enable Hotkeys
This way the command idles in the background until you switch the toggle back off, which re-enables everything.
If you want the toggle the other way around, you'd probably be best off with a command constantly looping in the background to monitor the status.
E.G.
Start Loop While : [{EXP:1=1}] Equals '1'
Begin Text Compare : [{STATE_JOYSTICK1BUTTON:1}] Equals '1'
Start VoiceAttack listening
Enable Hotkeys
Else
Stop VoiceAttack listening
Disable Hotkeys
End Condition
End Loop