In the constructor of the add-on (InformationCard.xml) you search for the form containing the 'object'. If it's not find OK, but if it's found you hook up to its submit event. The problem is that if I modify the DOM - remove the 'object' outside the form the cardspace selector is still triggered on submit. My point is to look for the form (and hook to its submission) after the user has selected a card. It's done this way in IE.