OK Bill,

Got it working, not exactly as I wanted but good enogh for now.

Thanks for the info on the MIDI THRU on the BK-7. It's not automatic, you have to go into the MIDI menu, then EDIT SYSTEM then paramaters, and finally SOFT MIDI THRU. The choices are OFF, GLOBAL, and PIANO. I set it for global. You also have to make sure you save it.

Now I can play both from the accordion! That's Great.

May still buy the BOX, cause I'd really like the T4 in fromt of the BK-7.

BTW, the accordion I'm using is a Roland 7X V accordion. It is quite a sophisticated midi controller!

Thanks again,
Don