How To Automate That 'terminal' Channel Fader

There was channel volume and pan fader added at the end of each channel DSP chain (default) in 1.9 betas.
How can i automate it or affect it some other way ?

For example i use gate plugin on track, and waht to slowly reduce output volume. If i automating channel volume - gate will recieve lover signal level and cut all underthreshold sound.
I know i can use internal Gainer this way, just curious, is it possible to affect that ‘terminal’ slider someway?

Cant you use and automate gain?