It is easy to extend these methods.
<script>
$.extend($.fn.menu.methods,{
showItem:function(jq, itemEl){
return jq.each(function(){
$(itemEl).show();
});
},
hideItem:function(jq, itemEl){
return jq.each(function(){
$(itemEl).hide();
});
}
});
</script>
Find a menu item with 'text' and hide it.
var m = $('#mm');
var item = m.menu('findItem', 'Save');
m.menu('hideItem',item.target);