I've had no luck on this. On related topic I was hoping to create a very simple "DJ" application that allows the user to load wav files into triggers (or buttons) and then play these sounds back. However, it seem this is not possible as all sounds must be added before the build process meaning that there exists no way to communicate between NodeWebKit and the Audio plugin in Construct 2.
I put a few posts up about it and got no response so I assume there is no answer to problem unless Ashley, et al. decide to support dynamic loading of sounds.