Map Tile culling problem

Hello there. This is a bit complicated so I apologise in advance for that.

I’m tiling a map using a set of tiles generated on the fly.

Here’s a link to the map as it is:

It’s still very rough but if you hover your cursor over the right hand side it scrolls that way.

The problem is, I can’t get it to remove the movie tiles which are out of view so it’s getting too cumbersome and sluggish.

I tried swapping the depths then using removeClip() but that didn’t work.

Any ideas would be ace. I’m drawing a bit of a blank…

Here’s how I’m adding the new tiles in case:

myDotArray[myY][myX+7] = myC.attachMovie("MapTile", sss, myC.getNextHighestDepth()+1, {_x:(myX+7)*108, _y:myY*108}); 
			myDotArray[myY][myX+7].doDot_string(superA[(myY*40) + myX+7]);

All the best