the 7speed DSG automatically disengages transmission anyway.
e.g. if you're driving on the highway, (automatic) 7th gear, 1800rpm, 80km/h. you take your foot off the gas pedal - the car will go into "neutral" and you can feel the car coast with minimal resistance. it reengages when you press on the gas OR brake pedal.
but the engagement wasn't smooth on my car (i've changed car now). it takes time for engagement and unless you pay a bit more attention and feather on the brake pedal early and light, the car feels jerky.