Hi,
I have also an 1st-Buffer with three cables +, - and Signal on it - my first consideration was to do that in the same way as you - but I haven't tested it myself yet, it will take a while, but I suspect that the firmware of the 1st buffer may not have implemented it yet, I seem to remember that there was a "*" after the specification and at the bottom, it will be possible in a later version (firmware) - but as soon as I get around to it, I'll still check whether it's already working and let you know -
Regards
Short addendum, try it with aux2...:
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