It seems that this answer along with its comments solves the problem using Karabiner. It's a bit complicated, so I'll post a full description here:
- Open Karabiner > Preferences
- Go to the tab "Misc & Uninstall"
- Click "Launch EventViewer"
- In the viewer, go to the tab "Devices"
You should see a table with several columns including "Vendor ID", "Product ID" and "Device Name".
- Identify your USB mouse in the "Device Name" column, and write down the corresponding "Vendor ID" and "Product ID"
- Go back to the Karabiner > Preference > Misc & Uninstall and now click the button "Open private.xml"
- This will open Finder where the file
private.xml is, open it with your favourite text editor
Edit that file to look like this:
<name>USB Mouse Scroll Reverse</name>
<autogen>__FlipScrollWheel__ Option::FLIPSCROLLWHEEL_VERTICAL, Option::FLIPSCROLLWHEEL_HORIZONTAL</autogen>
Note that you should replace the fields
productid to the values you previously wrote down (from the EventViewer device list).
- Save the file
- Go back to the window Karabiner > Preferences and now select the tab "Change Keys"
- Click the button on the top-right "Reload XML"
- You should see a new entry in the table below with the name "USB Mouse Scroll Reverse" (or whatever name you set in the XML file)
- Tick that box
That should be all!