Routesplit on OSX 10.x

The routesplit tool fails to make routes permanent on Snow Leopard and later versions of OSX.  To work around the issue edit the following file as such:

/Library/LaunchDaemons/net.routes.static.plist



...
<key>ServiceDescription</key>
<string>Install static routes</string>
<key>WatchPaths</key><array>
 <string>/Library/Preferences/SystemConfiguration
</string>
</array>
...