You could have VoiceAttack launch the game for you when it starts.
If you don't use VoiceAttack for anything other than that specific game, you could have it launch the game when the profile is loaded, using the "Run an Application" action in a command assigned to the profile-level "Execute a command each time this profile is loaded" option.
If you do use VoiceAttack for other purposes, you could create a desktop shortcut with the "-profile" and "-command" parameters to switch to the relevant profile, and execute a command to start the game.
Should you be using a third-party HCS Voice Packs product, you'd likely need to create a command in a separate profile, and then include that profile into the HCS Voice Packs profile, in which case you'd need to use the command line parameter(s), as commands from included profiles cannot be assigned to the options on the "Profile Exec" tab.