From badmuts@acadiane.org Thu May 29 16:35:15 2008
Subject:Re: MIDI upper and lower manuals of virtual B4 Hammond

> its NEXUS PLUS
> has 8 channels
> ,switch goes to 3 positions
> A
> M
> B
>
> I assume M=mute
> 1 -7,A & B MIDI holes in back
> one OUT in front

So try to connect your keyboards' midi outs to input 1 and 2 on this
thing, set the switch to M(erge) and connect the OUT to your USB-to-midi
gadget's MIDI IN.

Set B4 to receive on channels 1 for upper and 2 for lower and choose the
usb-midi-interface as input.
Set one of the keyboards to send on channel one and the other to send on
channel 2.
No need to use midi-ox or midi yoke yet, this should give you a working
setup.

(but also no need to uninstall it, it shouldn't get in the way and may
still come in handy, for example for translating the sustain pedal midi
message to a leslie speed change message)

Keep us posted.

P.s.: not sure what you meant by rotten out keyboard that didn't want to
change to transmit.
Doesn't it transmit anything whatsoever from its midi out?