Natural scrolling is an OS X feature so to make it work on windows, you gotta tweak Windows a little.
some google searches brought me to:
How to Get the Worst OS X Lion Feature in Windows (Reverse Scrolling)
However the scrolling is not as smooth and *natural* when i tested it.
Or you can create an AppleScript to quicken the process of toggling the Natural Scrolling within OS X.
found the following for you:
osx - OS X Lion Inverted Scrolling Automation Shortcut - Super User
The script works in OS X Yosemite, just need to allow it to run in Privacy settings.