There is no way to control the status of a button in kiosc from the LPU.
To control a toggle button status you need to send to kiosc the udp tag of the button + =on or =off.
For exemple if your UDP tag is "button" then sending "button=on" via UDP will activate it.
To control the LPU2 playbacks you need to set the UPD tag to 'pb../go+' and the LPU will send back a UDP message to kiosc giving the status of the playback with the form "pb../ac=on/off".
So it cannot control the button.
But what you can do is to add an 'indicator' in KIOSC above each button and set the UDP tag of the indicator to 'pb../ac'. This way when the payback is active the indicator will turn on, and off when the playback is inactive.
And you can even put the indicator over the button to make them looks as only one button.
I hope this will help you,
Enjoy
