FSX challenges in FS2004

Hey guys,On a whim, I installed the VFR Grand Canyon challenge meant for FSX into FS2004. Of course I had to create and place a flight plan into the flight's folder so the adventure could find it but it works..... after a fashion. It works just like a saved flight in FS2004 does now. I have no audio from the included challenge .wav files, and no "reward" when I land successfully. But, I do have the weather, etc. I can rename the HTM files and see those in FS2004 (although they are too large....Question, does anyone know what it would take to get the audio to work in FS2004?Thanks,Earl