Add this JUST AFTER
if($type == 'checkbox'){
:
$html = '<div class="'.$defaultclass.' '.$divclass.' togglecheck" id="tax-check-'.$c.'"><span class="taxolabel-'.$c.'">'.$taxlabel.'</span >';
$html .= '<input type="hidden" name="taxo['.$c.'][name]" value="'.$taxname.'">';
$html .= '<input type="hidden" name="taxo['.$c.'][opt]" value="'.$opt.'">';
Thanks for this; the plugin with this modification will definitely come in handy for me!