Trever,
we are playing now some days with that code get working in our templates and HTML emails. Code will be found, the tester at Litums says, but some parts are missing.
We tried to paste the code before the body end tag in HTML and in templated emails we tried in CSS editor and also in source of a text field.
Would be great if you can give us a hint how to do. Also which sort of field merger you are using.
Thanks
Hermann