A little update; in my Arch system I've downgraded xf86-input-evdev from 2.7.3 to 2.6.0 (built without mtdev) and now the scroll works perfectly in easystroke 0.5.5.1. I've had a lot of problem with all the 2.7 evdev drivers (from 2.7.0 to 2.7.3), so maybe this is not an easystroke issue.
A little update; in my Arch system I've downgraded xf86-input-evdev from 2.7.3 to 2.6.0 (built without mtdev) and now the scroll works perfectly in easystroke 0.5.5.1. I've had a lot of problem with all the 2.7 evdev drivers (from 2.7.0 to 2.7.3), so maybe this is not an easystroke issue.