The guy at Joomlart doesn't seem to understand the issue - he hasn't managed to get the radio box to appear in the Joomla template and hasn't understood that its their code
//frontend edit radio on/off - auto convert on-off radio if applicable
$('fieldset.radio').filter(function(){
return $(this).find('input').length == 2 && $(this).find('input').filter(function(){
return $.inArray(this.value + '', ['0', '1']) !== -1;
}).length == 2;
}).addClass('t3onoff').removeClass('btn-group');
that is changing the markup sent by the component. This javascript is FAR too aggressive and should not be affecting ALL radio elements inside a fieldset.
If you want a workaround - change "fieldset" to "div" in the file plugins/jevents/jevcustomfields/customfields/jevcfradio.php at lines 254 and 291.
BUT this is not a problem with our code its their javascript affecting too much on the page.