Getting sound to stop/start

Hi all,
im having a few problems with sound in our game. the initial idea was for players to follow sound until they reached the source, which would then trigger that sound off and another one to start up. my problem is, i cant get it to turn off. im using tutorial.base as my testing level and two audio emitters are placed in two different positions using the level editor and the following audio profiles

datablock AudioProfile(Testing0)
{
   filename = "~/data/sound/testing.wav";
   description = AudioDefaultLooping3d;
   preload = true;
};
datablock AudioProfile(Testing1)
{
   filename = "~/data/sound/footfall.wav";
   description = AudioDefaultLooping3d;
   preload = true;
};

the following code is what appears in the .mis file when i save the mission

new AudioEmitter(sound1) {
      position = "1.95515 -396.876 155.494";
      rotation = "1 0 0 0";
      scale = "1 1 1";
      profile = "Testing0";
      useProfileDescription = "1";
      fileName = "0";
      type = "2";
      volume = "1";
      outsideAmbient = "1";
      referenceDistance = "1";
      maxDistance = "5";
      isLooping = "1";
      loopCount = "-1";
      minLoopGap = "0";
      maxLoopGap = "0";
      enableVisualFeedback = "1";
      is3D = "1";
      coneInsideAngle = "360";
      coneOutsideAngle = "360";
      coneOutsideVolume = "0.25";
      coneVector = "0 1 0";
   };
//the same thing for sound2, except the profile is "Testing1"

the sounds are named sound1 and sound2. i have a trigger set up between them, so that when the player enters the trigger it will turn sound1 off and turn sound2 on. the trigger code looks like this:

$soundArray[0] = sound1;
$soundArray[1] = sound2;
$currPos = 0;

datablock TriggerData( SoundTrigger )
{
	// tickPeriodMS is a value is used to control how often the console
	// onTriggerTick callback is called while there are any objects
	// in the trigger. The default value is 100 MS.
	tickPeriodMS = 100;
};

function SoundTrigger::onEnterTrigger( %this, %trigger, %obj )
{
	echo( "entered the sound trigger");

        //alxStopAll();

        if($currPos != 1){
           alxStop($soundArray[$currPos]);
           $currPos += 1;
           alxPlay($soundArray[$currPos]);
        } else {
           alxStop($soundArray[$currPos]);
            $currPos = 0;
            alxPlay($soundArray[$currPos]);
        }
            
        Parent::onEnterTrigger( %this, %trigger, %obj );
}

whenever i enter the trigger, the sound doesn't turn off and the other one doesn't start up. i can get the sound to turn off if i use alxStopAll();, but there'll be other sounds going on (music, atmos, etc) and i don't want them to be affected. some times i can get the sound to play by calling the datablock (Testing0 or Testing1) and specifing a pos, but this is a bit hard to control and won't switch off when i call alxStop();. one thing i can get to work is when i enter the trigger zone, i can get the audio emitter to move to the second position.

so, the aim of this rambling, is a plea for aid. am i calling the alxStop() and alxPlay() wrong? how can i get it to work as i need it to? or, failing that, how can i change the audio file playing in the emitter, so i can just have it move position and play a different song. i'd prefer the first version, as there's plans for smaller sub-objectives using audio that need to be turned off when finished.
so, if you can make sense of this, and you know how to help, i'd appreciate it.
thanks