If your region is encased in a form you will have no access to the defaultCommand on your af:form. Try adding a subform to your fragement (jsff) and use its defaultCommand - note this will affect your naming. This should also work for popup buttons. ie. after your <jsp:root <af:subform defaultCommand="submitButton" id="s3"> ... your code </af:subform>
The Incident Archive: A blog to store my knowledge on the errors that I fix on a daily basis