ActionScript 2.0 :: Execute A Function MyFunction() When Roll Over A Button?

just need to execute a function - myFunction() when roll over a button i can do it coding the button like so:

[AS]on (rollOver) {
_root.myFunction(this);
}[/AS]

or code it in the root where i defined the function, like so:

[AS]myButton.onRollOver = function() {
myFunction(this);
}[/AS]

the thing is, i'm using this for a tween class animation, and when i code it directly in the button it works fine

can i write this AS diferent way?!
myButton.onRollOver = function() {
myFunction(this);
}