Is it possible to add behavior to a non-dynamic ActionScript 3 class without inheriting the class?

FooClass.prototype.method = function():String
{
    return "Something";
}

var foo:FooClass = new FooClass();
foo.method();

foo["method"]();

foo.method();

package
{
    public class Foo
    {
    	public var foo:String;

    	public function Foo()
    	{
    		foo = "foo!";
    	}
    }
}

package
{
    import flash.display.Sprite;

    public class footest extends Sprite
    {
    	public function footest()
    	{
    		Foo.prototype.method = function():String
    		{
    			return "Something";
    		}

    		var foo:Foo = new Foo();
    		trace(foo["method"]());
    	}
    }
}

public class FooWrapper extends Foo {

    private var wrappedFoo : Foo;

    public function FooWrapper( foo : Foo ) {
        wrappedFoo = foo;
    }

    override public function methodFromFoo( ) : void {
	    wrappedFoo.methodFromFoo();
	}

	override public function anotherMethodFromFoo( ) : void {
		wrappedFoo.anotherMethodFromFoo();
	}

	public function newMethodNotOnFoo( ) : String {
		return "Hello world!"
	}

}

public class SampleClass
{
    public function SampleClass()
    {
    }

    public function method1():void {
    	Alert.show("Hi");
    }

var actualClass:SampleClass = new SampleClass();

var QuickWrapper:Object = {
    ref: actualClass,
    method1: function():void {
    	this.ref.method1();
    },
    method2: function():void {
    	Alert.show("Hello!");
    }
};

QuickWrapper.method1();
QuickWrapper.method2();