Am using Garritan World Instruments VST software with Aria player.   Aria uses bass notes of keyboard as "keyswitches" to make bend notes/vibrato/termolo etc.   Problem - A-500 Pro has only 49 keys ie. keyswitches are out of range. Make Music say that only way to access keyswitches is if the A-500 supports assigning notes to one of its controllers.  
 
I sent this question to Roland customer support and, of course, got no reply.
 
Can this be done?
 
Thanks, Patrick