The "Auto Revoice" option of the keyboard automatically remaps midi voices to the appropriate internal programs. It is part of the Mixing Console edit pages (p124 of the Manual).

To get to it, press "Mixing Console" until the title of the window is "MIXING CONSOLE (PANEL PART). Then (if required) used "Next" or "Prev" to get to the "Vol/Voice" page. The buttons you need are "SONG AUTOREVOICE" and "SETUP" on the right hand side of the display. if "SONG AUTOREVOICE" is ON then the progam settings in midi files are replaced with those defined by the revoice settings - press "SETUP" to get to the map setting page which lets you choose the remap "strength" and also change the remap voices.

Hope this helps