You can do much more than play a voice. Once you midi the controller to the PSR you can have it act as if it is the PSR keyboard, ie drive accompaniment, voices, split the keyboard, record. You can call up presets, registrations etc - it will all work seamlessly. You go to settings, then midi and set the PSR to receive midi. Should all work automatically.
The PSR will work as normal, except you can play the Fatar keys. You can save the midi set up in a set up registration.
Mike