Redirect window in vaadin portlet

Hi everybody
I know in vaadin we can redirect to another window by getUrl(),
When i use vaadin portlet in liferay , i have use getUrl() but it redirect to 1 page in vaadin but not in liferay
if i configure it
com.vaadin.terminal.gwt.server.ApplicationPortlet2

it has error
Caused by: java.lang.RuntimeException: Internal problem getting window URL, please report

there is code

Portlet:

package urlwindow;

import com.vaadin.Application;
import com.vaadin.terminal.ExternalResource;
import com.vaadin.ui.Button;
import com.vaadin.ui.Label;
import com.vaadin.ui.Window;
import com.vaadin.ui.Button.ClickEvent;

public class UrlwindowApplication extends Application {

public void init() {
	final Window main = new Window ("My Test Application");
	setMainWindow(main);
	final Window mywindow = new Window("Second Window");
	mywindow.setName("mywindow");
	mywindow.addComponent(new Label("Has content."));
	addWindow(mywindow);
	
	
	main.addComponent(new Button("Click to open new window",
	new Button.ClickListener() {
	public void buttonClick(ClickEvent event) {
	// Open the window.
		System.out.println(mywindow.getURL());
	main.open(new ExternalResource(mywindow.getURL()));
	}}));
}}
	
	i have configure file web.xml,portlet.xml,liferay-portlet.xml


web.xm

<?xml version="1.0"?> urlwindow-portlet Vaadin production mode productionMode false Invoker Filter - ERROR com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter dispatcher ERROR Invoker Filter - FORWARD com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter dispatcher FORWARD Invoker Filter - INCLUDE com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter dispatcher INCLUDE Invoker Filter - REQUEST com.liferay.portal.kernel.servlet.filters.invoker.InvokerFilter dispatcher REQUEST Invoker Filter - ERROR /* ERROR Invoker Filter - FORWARD /* FORWARD Invoker Filter - INCLUDE /* INCLUDE Invoker Filter - REQUEST /* REQUEST com.liferay.portal.kernel.servlet.SerializableSessionAttributeListener com.liferay.portal.kernel.servlet.PortletContextListener urlwindow com.vaadin.terminal.gwt.server.ApplicationServlet Vaadin application class to start application urlwindow.UrlwindowApplication urlwindow Servlet com.liferay.portal.kernel.servlet.PortletServlet portlet-class com.vaadin.terminal.gwt.server.ApplicationPortlet 0 urlwindow /* urlwindow Servlet /urlwindow/* index.html index.htm index.jsp default.html default.htm default.jsp http://java.sun.com/portlet_2_0 /WEB-INF/tld/liferay-portlet.tld http://liferay.com/tld/aui /WEB-INF/tld/liferay-aui.tld http://liferay.com/tld/portlet /WEB-INF/tld/liferay-portlet-ext.tld http://liferay.com/tld/security /WEB-INF/tld/liferay-security.tld http://liferay.com/tld/theme /WEB-INF/tld/liferay-theme.tld http://liferay.com/tld/ui /WEB-INF/tld/liferay-ui.tld http://liferay.com/tld/util /WEB-INF/tld/liferay-util.tld [b] liferay-portlet.xml [/b] <?xml version="1.0"?> urlwindow /icon.png false urlwindow-portlet administrator Administrator guest Guest power-user Power User user User [b] portlet.xml [/b] <?xml version="1.0"?> urlwindow Urlwindow com.vaadin.terminal.gwt.server.ApplicationPortlet application urlwindow.UrlwindowApplication 0 text/html Urlwindow Urlwindow Urlwindow administrator guest power-user user

thank for help