title: paste_preprocess tinymce issue
body: <p>i want to strip all the html tags when pasting in tinymce editor. following is the code which is not functional... following is the tinymce settings... the paste_preprocess callback is not trigering... am i missing some option..?</p>
  
  <pre><code>tinyMCESettings = [ {
          mode : "none,textareas",
          height:heightEditor,
          width:'100%',
          plugins: "paste",
          theme : "advanced", //skin : "wp_theme",
          theme_advanced_buttons1 : "bold,italic,underline,strikethrough,|,justifyleft,justifycenter",
          relative_urls : "true",
          paste_use_dialog : false,
          paste_auto_cleanup_on_paste : false,
          content_css: styleSheetToLoadForTinyMCE + "?" + new Date().getTime(),
          force_p_newlines: false,
          setup: function (ed) {
              ed.onInit.add(
                  function (ed, evt) {
                      //resizeFrame1();
                      var a = tinyMCE.get(ed.id).getContent();
                      if(a.indexOf("hcRestrictedMode", 0) &gt; 0){
                          ed.getDoc().designMode = "off";
                          setTimeout(function(){
                              tinyMCE.activeEditor.dom.setAttrib(tinyMCE.activeEditor.dom.select(".hcEditable"), 'contenteditable', 'true');
                          }, 1000);
                      }
                  });
          },
          paste_preprocess : function(pl, o) {
              // Content string containing the HTML from the clipboard
              alert(o.content);
              o.content = o.content.replace(/&lt;.+?&gt;/,"");
          },
          paste_postprocess : function(pl, o) {
             // Content DOM node containing the DOM structure of the clipboard
             alert(o.content)
             o.content = o.content.replace(/&lt;.+?&gt;/,"");
         }
      }];
  </code></pre>
  
  <p>help here...
  thnx in advance...</p>