attachMovie Help

I am working on a simple animation of rain. However, I want the rain to have a ripple when it hits a pond-ish thing. I want to use attachMovie, of which I understand the basics. So, I tried some code WHICH WORKED except that when the movie was attached, it would a) be on the top left corner of the stage b) be on the _x and _y of the ground or c) be on the _x and _y of the raindrop. I want the splash to be where the raindrop hits the ground. Some example script:

onClipEvent(load) {
number = 0;
onClipEvent(enterFrame) {
if(_root.ground.hitTest(this)) {
_root.attachMovie(“ripple”, “ripple”+number,
number += 1;

Yes I am aware that when it says ‘_root.attachMovie’ Flash attaches the MC
to the _root. and that if it says ‘_root.ground.attachMovie’ attaches the MC to the ground, etc. What I need to know is how to tell the MC to have the _x and _y of where the raindrop hit the ground. Hope that makes sense, and thank you!