Sorry bout the delay Zahael... got there in the end (at last)
I could play the sound file in my sound editor no problems, however it was a bit quiet...
This is the sound you play with playsound is it?
It may be too quiet to be heard from far away...
I suggest setting up a dummy mission and seeing if you can recreate the scenario without having to sit through your whole mission just to test it. Then you can tweak and test very easily, and just cut and paste into the real mission once you're satisfied with the result...