Didier - when crawling at very low speed (after being stood still) the computer rides the clutch to make sure the car doesn't stall - as a "human" driver would do
If you give it more gas and hence increase your speed a little more then the computer can disengage the clutch entirely as the car has effectively pulled away..
Basically if you sit still in traffic and let a small gap open up in front of you then give it enough gas to disengage the clutch and then come to a complete stop again when you've caught up with the car in front then that would be ideal: Clutch out then clutch in.
Alternatively if you crawl forward at very low speed following the car in front then the computer will ride the clutch all the way until the traffic is moving fast enough for you to give it enough throttle to disengage the clutch fully.
Being gentle and crawling is not actually doing the car as much good as moving forward in small quick bursts. We're not talking about LAUNCHING the car forward - just enough speed to not ride the clutch ~ 5mph?
I know the F355 has a twin plate clutch but I'm really not sure about the 360... (it's a lot lighter in the manual than the 355 for sure).