I tried this out and indeed I can change the colour of the pad but what does not change is the internal state of the pad in the controller. That is, I can take a pad which is "off" give it a colour to make it appear to be "on". When I then hit the pad, the controllers sends the midi command that the pad just came "on", i.e. going from off to on instead of going from on to off.
So is there a second sysex command to activate a pad in addition to setting it's colour?
UPDATE: to answer my own question it's the following sysex command:
F0 00 20 6B 7F 42 02 00 00 7n vv F7
where
n is the pad number, 0 to F, corresponding to Pad1 to Pad16
vv is the value - for me this is 0x00 or 0x7F as my value range is 0 to 127
(The parameter/slot for the colour is 0x10 while for the current value of the pad it is 0x00, hence the 10 has been replaced by 00)
I got this by querying the controller using the sysex command and also the midi logger in the midi control center. Details on the sysex query command can be found here
https://www.untergeek.de/2014/11/taming-arturias-beatstep-sysex-codes-for-programming-via-ipad/basically it query values becomes:
F0 00 20 6B 7F 42 01 00 pp cc F7
where
pp is the parameter number or slot number - because each control has a bunch of settings stored in slots
cc is the control number (for the pads that is 0x70 to 0x7F)