Disklavier

I need help please with my Mark III B version (DGC1-B). I have used VanBascos's software per carol's recommendation and am using the USB-MIDI cable I bought from Ebay. The ToHost selector is set to midi and the cable powers up and recognized by he computer. When I play a song in vanbasco, the blue light on the cable flashes showing the data is going through the USB cable into midi in/out. The problem is I can not get the piano to play it. When I turn the disklavier on, it is still on the internal drives. Doesn't have to be on an external midi selection? I can't find such selection. Any help is appreciated.

Bob