Comment # 3 on bug 904984 from Federico Vecchiarelli

As a work-around, I'm able to get this to work if I bypass GNOME by editing:

/etc/X11/xorg.conf.d/50-synaptics.conf

I can then add the following options:

   Option  "VertEdgeScroll" "1"
   Option "VertTwoFingerScroll" "0"

Only then it works as expected (overriding GNOME's settings of course).
Enabling Vertical Scrolling alone is not enough as Two Finger Scrolling was
still working at that point. I had to add another option to stop the two finger
scrolling from working.

Anyway, while I now have this fixed, this should be working from GNOME without
having to edit the above mentioned file.

Regards,

Fede