Nested button function trouble - please help!

//This is my original code which works fine when my button is present on the root timeline
btn_up.onRelease = function() {
getURL(“javascript:Launch(‘website.html’, 2000, 1200)”);

};

[COLOR=“Blue”]//The button is now nested within a mc in an external swf which is subsequently loaded into an empty container (signpost) on my root timeline. I’ve attempted to target it but can’t get it to function. Can anyone advise pls?
_level0._root.signpost.sign_group.map2.img.button.btn_up.onRelease = function() {
getURL(“javascript:Launch(‘website.html’, 2000, 1200)”);
};[/COLOR]