noob OnMouseMove question

Hi All, I'm mucking around with a trial version trying to get the hang of it and thinking about getting a license.

For my first non-tutorial game I decided to try and remake a missile defence game I used to play Back In The Day (TM).

Anyway, to the point, I'd like to make a turret that points towards the current position of the mouse. I tried doing this via behaviours and the turret will point towards the mouse but only if the mouse is actually on the turret.

So I decided to make a fireZone trigger area, and use it's onMosueOver function through scripting to pass the info to a function on the turret class, like so:

function fireZone::onMouseMove(%this, %modifier, %worldPos)
{
%mousepos = %worldPos;

$PT.face(PT, %modifier, %mousepos);
}

$PT is defined in the onLevelLoaded for the turret as such:

function playerTurret::onLevelLoaded(%this, %scenegraph){
$PT = %this;

}

The function is called properly, but for some reason %mousePos is set to 0,0 when it's passed to playerTurret.face

Is this due to variable1 = variable2 assigning variable1 as a pointer to variable2? If so how do I get a full copy of the %worldPos variable for passing along the function/ how can I get onMouseMove to work when the mouse is not on the object in question?

Cheers
-Galcian