I tested.
VoiceAttack full version v1.8.8 64bit
VAJoystickOutput_v6
JoystickOutput.vap
When I ran "test stick" I got the following message:
3:54:33.726 Plugin has not completed initialization. This may occur if you are running the plugin on profile startup and vJoy has not had a chance to initialize. Please try again.
I did it after I had enough time to initialize it.
There was no response to vJoy Monitor.