The simplest way would be to merely include copies of the wav files as part of your WAR and not attempt to kludge around things.
Relocating the entire WAR (as Ulf suggested) probably wouldn't do what you wanted, since the ENTIRE war has to be relocated, but depending on how things are set up, it might be a possibility.
Windows added a file aliasing feature similar to Unix/Linux softlinks a few years back, and this can be used to make the WAV directory appear to be part of the WAR, although you may have to change some settings in server.xml, since softlinks are somewhat of a security issue and thus disabled by default.
And then there's the old standby: write a
servlet that copies the WAV from its actual external home out to the HttpResponse output stream (which is what the default servlet does for in-WAR files anyway).
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.