Icefaces Liferay portal navigation JSF problem

Question

I have a final Submit button in my Application looks like :

public String finalSubmitNavigate(){

   // LOGIC HERE!
    FacesContext.getCurrentInstance().getApplication().getNavigationHandler().handleNavigation(FacesContext.getCurrentInstance(), null, "success");

  return "success";

}

I have also set navigation case in my faces-config.xml file:

<navigation-rule>
        <from-view-id>/Application.jsp</from-view-id>
        <navigation-case>
            <from-outcome>success</from-outcome>
            <to-view-id>/Page1.jsp</to-view-id>
        </navigation-case>
    </navigation-rule>

the function finalSubmitNavigate() is set as the action of a button in my application. the logic is writing data to database and is working fine. However, the navigation doesn't occur. I have tried without the FacesContext....getNavigationHandler() also and it didn't work. I have also tried Page1.iface instead of Page1.jsp in the faces-config.xml.

Do you know what's wrong? or what am I missing?

Thanks,