If you are comfortable modifying the javascript within the PHP code, you will find that here:
If you are able to work with PHP and GitHub, or know a developer who can, adding an option within the plugin to be able to add ga() commands like this would make for a good enhancement and pull request.
Thank you for this. I have a very basic confidence with PHP and especially with GitHub, but I can see if I can find somebody to help on this.
I also believe that an option for enabling IP Anonymization would be very useful.
All the best,
Leonardo