Help with AS 2.0 Class and assignment to MovieSymbol

Hi, I have made a Picture class, and have it in a function called center. It’s supposed to center the picture on the stage. It is defined as follows:

	public function center()
	{
		trace("Centering picture.");
	}

I have also created a MovieClip symbol in my library called PictureHolder and assigned the Picture class to it. When I tried to execute the center function through an instance of the PictureHolder symbol, nothing is traced.

[size=1]Example: [/size]

pH.center();

where pH is an instance of PictureHolder and is on the stage.

I’m new to this, any help would be appreciated. Thanks =)