[etc]

Может все-таки use уберем? Плюс скорее:

package core.sub {
	import core.CoreClass;
 
	/**
	 * @author					etc
	 * @version					1.0
	 * @playerversion			Flash 9
	 * @langversion				3.0
	 */
	public class SubClass {
 
		public function SubClass() {
			super();
		}
 
		/**
		 * @private
		 */
		private var _ns:Namespace;
 
		public function set ns(value:Namespace):void {
			if (this._ns === value) return;
			this._ns = value;
			(CoreClass[new QName(this._ns, 'test')] as Function)();
			CoreClass.value::test();
		}
	}
}

package core {
	import core.sub.SubClass;
 
	/**
	 * @author					etc
	 * @version					1.0
	 * @playerversion			Flash 9
	 * @langversion				3.0
	 */
	public class CoreClass {
 
		public function CoreClass() {
			super();
			var s:SubClass = new SubClass();
			s.ns = sub;
		}
 
		private namespace sub;
 
		sub static function test():void {
			trace('Sub test');
		}
	}
}