Hello Paul,
As far as SVG support is concerned, the API supports external (linked) SVG files and dynamic SVG generated by JavaScript. It does not handle static inline SVG. So to print an SVG file, you need to link it from HTML.
An example: paste the following code to
this form and click "Convert to PDF".
<img src="https://dl.dropboxusercontent.com/u/9346438/tmp/chart.svg"/>