and see what value VertTwoFingerScroll has. You can change it with synclient two. Use --help to see how it works. You'll probably need to run it every time you log in. There should be a way to do it with a xorg.conf.d file, but I'm not bothering with it.
I tried to make it work but failed I have to do without scrolling somehow. EDIT: the touchpad is mistakenly recognized by the kernel as PS/2 Logitech Wheel Mouse and that is why it doesn`t work as expected.