how do you assign a switch to a record button on a selected clip slot

Hi –

Just getting started with CSS & a bit confused.

I’m want to set up a foot control switch (a Boss FS-5U) to record a new clip in an empty clip slot in Session view.

Using MIDI Mapping, I can assign the switch to the Clip Record button on an empty slot.
If the track is record armed, pressing the switch (a momentary CC message) starts recording.
Pressing it again stops recording & starts playback.
But of course the switch is hardwired to that particular track/clip.

Using CSS, I’d like to be able to highlight a particular empty clip slot and have the FS-5U switch affect that specific clip.

But there don’t seem to be any mappings for Clip Record/Stop buttons.

I’m sure I’m missing something obvious, but I can’t figure out what.

Thanks in advance.