A bit of a play around (whilst admitting I don't really know what I'm doing) seems to indicate something more is needed than just detecting 'script type="text/x-mathjax-config"'.
Inspecting the preview window with a <math ...> line and grabbed the inserted MathJax script and added that to a "simple" file, but it doesn't render:
Using the random google-found script line I mentioned earlier does render:
I'm hoping(!) that I can get this simple sample to render: