AS2 - Button in a Clip

G’day Kirupa. Long time reader, first time poster.

I have been searching around for the answer for this dillemma for awhile now. The problem is, i cannot click a button inside a movie clip because the mouse click is being “intercepted” by some of my other code. Ive been working for hours, so maybe my brain has had enough and its a simple answer. But i just cannot get the button to work. The code i allready have in place is used to drag the movie clips around the stage and is as follows.

onClipEvent (mouseDown) {
if (this.hitTest(_root._xmouse, _root._ymouse)) {
this.swapDepths(_root.adeep);
this.startDrag();
}
}

Any Help would be greatly appreciated.
Regards, Chris