Hi John,
While I haven't tried this with every voice on my expansion cards, I've been able to take many and go to Voice Edit and then select Tone to see that the expansion card voice is made from the original tones in the keyboard. Add the same processing, change the name and put it into Sound Memory. Now you have an expansion voice that any KN7000 can play. When I was sharing songs with other Zoners I never heard of any problems with the new voices.
Of course this doesn't solve your need to get the voices on the fly.
Frank