Add the ability to assign a bus send fader to custom controls and a fader strip

It is possible to send a bus master signal from bus 9-16 to bus 1-8 (bus→bus sends).

Now, it is furthermore possible to use at custom controls the function “fixed bus send”. for that function you have to choose the channel and the send bus, so I can assign Channel 1 to Bus 1. So far so well.

But it is not possible to select Bus 9-16 as “channel”. But it would be really helpful to be able to to that.

BTW: you also cannot use this function to assign a matrix 1-8 send or main 1-4 send.

And please add this also to the Fader assignment functions.