I tried the single cable midi loopback suggestion on my ES920 as suggested by James and it worked. There is not much you can do to adjust the sounds but I was able to split and layer with on-board sounds. There is a Van Halen 'Jump' patch as well as a few guitars and pads. Nothing to write home about but nice to know I can play around with them. The program change numbers are in the separate midi manual for the ES920.