You should keep your constructors in your ValueObjects empty or else you might overwrite received data accidentally.

 

Sample
class PersonVO
{
    public var books:Array; // of BookVO

    //Constructor
    function PersonVO()
    {
        books = new Array();
    }
    ...
}


When you get the data from the server the constructor is called after all of the values are set, so you'll overwrite the received data.

Read more here