Changing SysEx messages in Events View

I represent Rodgers Organs here in Minneapolis.  Our organs are completely MIDI compatable and I use Sonar 7 to record and playback.  But now I have a client who has recorded his Yamaha Clavinova on Cakewalk. He wants this to play on one of our organs but the organ had different SysEx messages for the organ stops than his clavinova.  I have heard that I can record organ piston changes on HS7 without playing any notes.  Then I can go to the Events View and copy the piston changes which contain SysEx data and replace the Yamaha SysEx with mine.  The goal is to have the organ play his recorded notes but use my SysEx from the organ and paste those into his Events.

Any suggestions?  Thanks much