The polyfill cannot reproduce audio of this SVG animation

I get no audio when reproducing SVG animations with your polyfill.
I'm trying to reproduce this SVG animation file of a cartoon episode on IE. It was exported to SMIL SVG from Flash with the excellent Flash2Svg plugin ( https://github.com/TomByrne/Flash2Svg  ):

http://www.tbyrne.org/portfolio/smil/LoveDota.svg

Is this a known issue?
