Controlling components from class file?

I’m trying to control a component (a Slider) from a class, but it won’t work, because I can’t load the definitions (import fl.controls.Slider; import fl.events.SliderEvent; --> Error 1172: Definition not found).

The Class I’m using loads the .swf containing the Slider, that’s working fine and I can also adress the slider-component and read it’s value. But I can’t invoke a SliderChange.Event …
I read, that you have to add components to the library to be able to load the definitions, but that’s only possible in .fla files…

Thank you

Peter