So, I think your asking how to add a .wav file as a proximity alert sound? If so, you name the .wav file the same name as your .gpx file, i.e. roadblock.gpx & roadblock.wav, and make sure they are in the same folder, so when your near the point the gps will play the .wav sound. Good Luck!
That means that i cannot load wave files that are not part of a GPX file.
If i were to load two wave files with the same poi name would i get two warnings for the one poi , or will one of the wave files take precedence over the other. The reason i ask is i have lost the bong warning sound for the schools zones, could be that i deleted the garmin GPI files on the unit and originally had doubled up on the poi files.
school zone.wav (voice)
school zone.wav (beep)