Portlets in Vaadin7

I am evaluating Vaadin as web framework for portal server (liferay) and had build a few porlets using Vaadin6. I have upgraded the software stack (eclipse/liferay/vaadin) to the latest version vaadin 7.0.7 and have serious problems with my portlets. Classes/interfaces have been deprecated and no clear alternative are provided in the doc.
public class MyApplication extends Application implements PortletListener, PortletRequestListener
public class MyApplication extends UI implements PortletListener
or ??
public class MyApplication extends VaadinPortlet
or ??

It seems that the handleXXXRequest methods are not properly called ??
Does anybody have working Porlet 2.0 - vaadin 7 code working that he can share ? I understood that the portlet doc will be reworked but for the time being it is very hard to figure out how to migrate the porlets to vaadin 7.