Auto-rest feature in custom workouts

I recently bought my Forerunner 245 and trying to use the new auto-rest feature in rest intervals of a custom swim workout, but auto-rest does not seem to be an option for 'rests'. 

I tested with a short custom running workout and auto-rest does not appear to kick in - tried using 'until lap button' and 'time' options

If you have found a way to incorporate it, please share.