"onMouseDown" working, can't get "onMouseWheel" to work

I’m using AS2, I have a simple class in an external .as file. I have it extend MovieClip and I have a few functions that work great, such as “function onMouseDown()” and “function onMouseMove()”.

Now I want to do the same with onMouseWheel. The only problem is that I can’t get it to work without specifying in the constructor for the class “Mouse.addListener(this);” But this causes my other functions (such as the onMouseDown and onMouseUp) to register twice, so it sees every single click as a double click.

Is there something I am missing? Thanks for any help.