Problemas com o interceptador scope struts 2

Assuntos Gerais
#1

não estou sacando qual e o problema desse codigo. alguem pode me ajudar ???

public class WizardAction extends ActionSupport implements
		ModelDriven<Usuario>, Preparable {

	private Usuario usuario;
	private String nome;
	private String sobrenome;

	public void setNome(String nome) {
		this.nome = nome;
	}

	public void setSobrenome(String sobrenome) {
		this.sobrenome = sobrenome;
	}

	@Override
	public Usuario getModel() {
		// TODO Auto-generated method stub
		return usuario;
	}

	@Override
	public void prepare() throws Exception {
		// TODO Auto-generated method stub
		usuario = new Usuario(nome, sobrenome);
	}

}
 <%@taglib prefix="s" uri="/struts-tags" %>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<s:form action="Wizard">
<s:textfield label="nome" name="nome"></s:textfield>
<s:textfield label="sobrenome" name="sobrenome"></s:textfield>
<s:submit></s:submit>
</s:form>

</body>
</html>
<struts>
	<package name="mypacke" extends="struts-default">

		<interceptors>
			<interceptor-stack name="eventStack">
				<interceptor-ref name="scope">
					<param name="session">model</param>
					<param name="autoCreateSession">true</param>
				</interceptor-ref>
				<interceptor-ref name="paramsPrepareParamsStack" />
			</interceptor-stack>
		</interceptors>

		<default-interceptor-ref name="eventStack"></default-interceptor-ref>

		
		<action name="Wizard" class="TesteAction.action.WizardAction">	
			<interceptor-ref name="eventStack">
				<param name="scope.type">start</param>
			</interceptor-ref>
			<result name="success">/Form1.jsp</result>
		</action>

	</package>

</struts>
<%@taglib prefix="s" uri="/struts-tags"%>
<%@page import="negocios.Usuario"%>
<%@page import="java.util.Enumeration"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
	out.println(session.getAttribute("nome"));
	out.println(session.getAttribute("model.nome"));
%>

</body>
</html>

os 2 resultados estão dando null !!
não estou conseguindo colocar informações dentro da session com o interceptador scope… alguem poderia ver o que tem de errado nesse codigo ???

#2

Como está o seu web.xml?

#3

ta ai meu web.xml

<web-app id="WebApp_ID" version="2.4"
	xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<display-name>Wizard</display-name>
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>

	<filter>
		<filter-name>struts</filter-name>
		<filter-class>
			org.apache.struts2.dispatcher.FilterDispatcher
		</filter-class>
	</filter>

	<filter-mapping>
		<filter-name>struts</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

</web-app>
#4