I've finally done it, thanks to your help for the scroll (I wanted to enable a 360° scroll).
I used the behavior rotation combined with Touch.SpeedAt to continue the rotation after the user releases the touch (and a positive/negative acceleration depending on wich side it's turning to make it stop).
Here is my .capx for those who might have the same question :
[attachment=0:2umkttaw][/attachment:2umkttaw]
Thank you Shinkan