FlexBindingExample.as

// All you needed to do if you wanted codegen:
[Bindable]
public var easyProp:MyClass;

// More explicit version using a named event:
private var _myProp:MyClass;

[Bindable("myPropChange")]
public function get myProp():MyClass
{
  return _myProp;
}

public function set myProp(value:MyClass):void
{
  if (_myProp == value) return;
  _myProp = value;
  dispatchEvent(new Event("myPropChange"));
}