A question about document class

hello

i have one generic class (GenericDocumentClass.as) as my document class for all external .swfs that i’m using which contains a public var test:String

for example in sample.swf

package {

public class Sample extends GenericDocumentClass{
public function Sample(){
var hello:Hello = new Hello();
addChild(hello);
}

}

}

in the hello class im using the following syntax Sample(root).test (to retrieve the value of test string) but is null.

the sample.swf is loaded into Main.swf

any help?