Channel Switching on RH150G3

I just bought a new RH150G3 and realized that the footswitch plug is a midi plug. Like all other footswitch. I will also buy a G-major in the following weeks so I don't have it right now. My problem is that I want to drive the amplifier channels with the G-Major's channel switching feature.
The G-Major have 2 relay switching, so say I want just the two first switch to have a relay (clean to overdrive and gain 1 to gain 2).
I will have to make a cable which will have an end with midi plug and the other end will be a trs stereo plug. So how to wire all this out?

Thank you very much
Michael

I have the same problem! But i think the randall rh150g3 footswitch is
just a standard designed for randall amps, so not exactly "midi" i THINK.
because it has to many pins. About channel switching, i think the best
solution is to buy a rocktron midi mate (it's affordable) and connect is with your gmajor + rh150g3. then u can switch channel a,b on the head and channel 1,2 from the effect processor at the same time with the push of 1 button. I never figured it out so i'm gonna try to get a midi controller next week and i'll post if i got something out of it.

The G3 footswitch isn't MIDI. It's basically 4 switches with a common ground, so rather than have the 4 cables coming out, a 5-pin cable/socket is used.
Easiest way to find out the wiring is to pop the back off the footswitch box and take a note of what each pin on the 5 way goes to.

Anyone knows which pin behave on which state of this amp?
I have opened the footswitch but the midi plug is closed, nothing to see...

thank you