Thanks Lugia
The clever boffins at Befaco suggested: although the Zeus acces is not compatible with the bus, as the bus need tree poles (+15/-15/ground). Anyway, you can make your own access module, with a piece of plate and a 3 pole connector.
I asked if they reckoned I could cannibalise/modify the access plate with a three pole connector to which they responded: Yes probably you can. just need to find a three pole connector and make your own cable to it.
Maybe this plug (very safe and sturdy model)
https://www.rapidonline.com/cliff-electronic-fc684203-skt-microphone-3pin-panel-mounting-male-50-3229
with this on the cable:
https://www.rapidonline.com/cliff-electronic-fc684213-plug-3-pin-straight-on-cable-6mm-female-50-3215