I think I have the same problem.
I recorded a .wav file called MK PBX.wav
I went into the OGM VoIP Call Attendant Start.
I changed the audio to the file above.
I play it in the OGM settings, and it plays.
I close that and Play it in the OGM Manager and it works
I play the simulator and it is a synthesized voice.
When I call the number it is a synthesized voice.
What am I doing wrong.
Very Frustrating.
Max