Well, the control switcher is just the interface to the amp. When I had my Shiva, I used a Ground Control Pro for the footswitch so there was no real message set up, it was just like setting up a GCX with the GCP. You are essentially turning loops on or off. I still use the control switchers but now with my XTC heads and it works the same way as with the shiva, there are just more options. I also have switched to a Boss ES-8 and for that I send basic program changes to the control switchers.
Not sure how the musicom works but in the Boss the basic workflow is to set up a patch (midi channel and program change #) and assign it to a button on the ES-8. Then Tap that button to send the PC message to the control switcher, then on the control switcher configure the switches to the desired combination for channel/boost desired, then save the combination on the control switcher. At that point the control switcher will recognize the PC# it is being sent when you step on a footswitch button and recall the combination you saved for that PC #.
To be more specific... I edit a patch and pick the midi channel on which control switcher I want (I use two of them) then I pick a PC # (There are 8 buttons on the ES-8 so I use PC #s 1-8) to send and save the patch. Then, on the ES-8, I push the button that the patch is assigned to once again (This sends the PC # to the control switcher). Then I go to the control switcher and set the loops on/off as desired to hit the channel/boost combo I want, then press/hold button 1 and button 3 (i think), all lights will flash and that indicates the control switcher has saved the program.
I use medusa cables to convert from the Bogner 8 pin din connector to TRS jacks and plug them into the control switcher. There are only 4 ports on the control switcher so I plug the jacks for channels 1-3 into ports 1-3 and then I use a mono Y cable to plug both boost jacks into port 4 of the control switcher.
Sorry for the long post but hope it helps. If needed I can probably record a phone video of the process and send if you need. Took me a minute to figure it out but once I did, its a breeze.