FlashMX04 - (probably) simple scrolling map problem

Ok, So all I need is a few other sets of eyes to look at this script. I feel like a total idiot cause I can’t figure out what I have to do to make this work…
I’m not entirely sure how to explain the problem, but here goes…

Here’s a link to the file…
Scrolling Map

And this is the code…

 
ease = 3; 
 
mapMC.onEnterFrame = function() {
 
mouseX = _root._xmouse;
mouseY = _root._ymouse;
 
curX = mapMC._x;
curY = mapMC._y;
 
newX = curX+mouseX;
newY = curY+mouseY;
 
mapMC._x = curX-(newX/ease);
mapMC._y = curY-(newY/ease);
 
};

I want the map’s movement to be constrained to the edges of the stage. Or in other words, if you move your mouse from the left edge of the stage to the right, you only just see the right edge map, whereas now, it dissappears off the other side of the stage…

Thanks in advance!