I've got an s:form with sj:submit and s:submit inside, sj:submit works properly but s:submit buttons doesn't works. Nothing happens when I click on s:submit buttons.
I tried to use sj:submit button outside the form and linking that to s:form with formIds parameter.
I solved using:
<s:submit onClick="overrideSubmit('this_action')"/>
and
function overrideSubmit(actionName) {
document.forms['configurationForm'].action = actionName + '.action';
document.forms['configurationForm'].submit();
}