Comment 34 for bug 1368402

I came across this in a Debian bug (https://bugs.debian.org/823195) and I found a workaround similar to comment #2. This works on Debian Sid, but not on Jessie, so this might not work on a system more than a year or two old.

Use normal (non-natural) scrolling in Xfce settings and run a command like:

  xinput --set-int-prop 12 "libinput Natural Scrolling Enabled" 8 1

You might have to replace the "12" with the ID of your mouse, which you can find with "xinput list". I think this is what GNOME's mouse settings does to enable natural scrolling.