This is a small example showing how to load an animated SVG.
dropbox.com/s/w66ch2oks77qzl1/Animated%20CSS.c3p
The SVG is in it's own file and is loaded into the HTML element using the AJAX plugin. The animation is defined in a separate CSS file which is loaded automatically by setting it's purpose to "Stylesheet"
I haven't tried it, but you could also choose to define the SVG and CSS directly in the Content property of the HTML element instance.