The toolbar items needed to be disabled going to this string. Example DisabledItems="Bold, New, Delete"
Example
<?php
$rte=new RichTextEditor();
$rte->Text="Type here";
$rte->DisabledItems="Bold, New, Delete";
$rte->ID="Editor1";
$rte->MvcInit();
echo $rte->GetString();
// use $_POST["Editor1"]to retrieve the data
?>