As a result of adding the options from README.alps to the TouchPad section, the USB mouse didn't work anymore.
I followed Loïc's suggestion of removing the whole touchpad section and leave only the default mouse as input device and now I have both the USB and my touchpad working ok for me: the touchpad tapping works fine, but the scrolling doesn't (anyway, I don't like the touchpad scrolling).
As a result of adding the options from README.alps to the TouchPad section, the USB mouse didn't work anymore.
I followed Loïc's suggestion of removing the whole touchpad section and leave only the default mouse as input device and now I have both the USB and my touchpad working ok for me: the touchpad tapping works fine, but the scrolling doesn't (anyway, I don't like the touchpad scrolling).