Vaadin + Shiro + Guice

Hi there...
I just got SHIRO + VAADIN + GUICE working... now Shiro aop module is not more ignoring annotations in my views.
But... I just realized I'm not able to bind shiro Subject to vaadin session... so every time I check subject (SecurityUtils.getSubject()) for authentication or permissions  (throug annotations or by code)  I get a new subject because it's bind to thread.
How can I solve this?

public static Subject getSubject() {
        Subject subject = ThreadContext.getSubject();
        if (subject == null) {
            subject = (new Subject.Builder()).buildSubject();
            ThreadContext.bind(subject);
        }
        return subject;
    }