some problem with a TRISTATE

Hello, I'm trying to make some "quote selected text" button to insert any selected text on the page to the FCKeditor.
My problem is that I want to keep the 'blockquote' button behavior. So one button must do the following things :
1) Insert any selected text on the page to the FCKeditor in [blockquote] tags
2) Quote selected text in the FCKeditor (as 'blockquote' button)
3) Unquote current line or selected text if it is a quote in FCKeditor (as 'blockquote' button)
I have already done that. But my problem is that my button is not firing (FCK_TRISTATE_ON) when cursor is in the [blockquote] tag in the FCKeditor.
Here is my code. I took the plugin 'InsertHtml' by Paul Moers (http://www.saulmade.nl/FCKeditor/FCKPlugins.php) as a base.
GetState function is just a copypaste from '/_source/commandclasses/fckblockquotecommand.js' but it seems not working (?)

/*
 * Licensed under the terms of the GNU Lesser General Public License:
 *       http://www.opensource.org/licenses/lgpl-license.php
 * 
 * File Name: fckplugin.js
 *    Plugin to add some preset HTML
 * 
 * File Authors:
 *       Paul Moers (http://www.saulmade.nl/FCKeditor/FCKPlugins.php)
 */

   // insertHtmlObject constructor
   var insertHtmlToolbarCommand = function()
   {
   }

   // register the command
   FCKCommands.RegisterCommand('insertHtml', new insertHtmlToolbarCommand());

   // create the toolbar  button
   var insertHtmlButton = new FCKToolbarButton('insertHtml', FCKConfig.insertHtml_buttonTooltip || FCKLang.inserHTML_buttonTooltip);
   insertHtmlButton.IconPath = FCKPlugins.Items['insertHtml'].Path + 'images/toolbarIcon_default.gif'; // or pick any other in folder 'images'
   FCKToolbarItems.RegisterItem('insertHtml', insertHtmlButton);

   // manage the plugins' button behavior
   /*
   insertHtmlToolbarCommand.prototype.GetState = function()
   {
      return FCK_TRISTATE_OFF;
   }
   */
   insertHtmlToolbarCommand.prototype.GetState = function()
   {
    
      // Disabled if not WYSIWYG.
      if ( FCK.EditMode != FCK_EDITMODE_WYSIWYG || ! FCK.EditorWindow )
         return FCK_TRISTATE_DISABLED ;

      var path = new FCKElementPath( FCKSelection.GetBoundaryParentElement( true ) ) ;
      var firstBlock = path.Block || path.BlockLimit ;

      if ( !firstBlock || firstBlock.nodeName.toLowerCase() == 'body' )
         return FCK_TRISTATE_OFF ;

      // See if the first block has a blockquote parent.
      for ( var i = 0 ; i < path.Elements.length ; i++ )
      {
         if ( path.Elements[i].nodeName.IEquals( 'blockquote' ) )
            return FCK_TRISTATE_ON ;
      }
      
      return FCK_TRISTATE_OFF ;
   }
   
   // insertHtml's button click function
   insertHtmlToolbarCommand.prototype.Execute = function()
   {
      if (FCKConfig.insertHtml_showDialog)
      {
         var dialog = new FCKDialogCommand('insertHtml', FCKLang.insertHtml_dialogTitle, FCKPlugins.Items['insertHtml'].Path + 'insertHtml.html', 200, 100);
         dialog.Execute();
      }
      else
      {
      
      var txt = getSelectedText();
      if(txt == ''){
        //var selection = (FCK.EditorWindow.getSelection ? FCK.EditorWindow.getSelection() : FCK.EditorDocument.selection);
        //txt = getSelectionHTML(selection, FCK);
        FCK.Commands.GetCommand('Blockquote').Execute();
        
      }
      
      if(txt != ''){
        FCK.InsertHtml('<blockquote><div>'+txt+'</div></blockquote>');
      }

         FCK.EditorWindow.parent.FCKUndo.SaveUndoStep();
      }
   }

// get selection text from anywhere on the page
function getSelectedText(){
    var containerWindow = FCK.EditorWindow.parent.parent;
    var containerDocument = containerWindow.document;
    
    var txt = '{default value}';
    if (containerWindow.getSelection){
        txt = containerWindow.getSelection();
    } else if (containerDocument.getSelection) {
        txt = containerDocument.getSelection();
    } else if (containerDocument.selection) {
        txt = containerDocument.selection.createRange().text;
    }
    return txt;

}   


// get HTML from selection
function getSelectionHTML(selection, editorInstance)
{
    var range = (editorInstance.EditorWindow.parent.FCKBrowserInfo.IsIE ? selection.createRange() : selection.getRangeAt(selection.rangeCount - 1).cloneRange());

    if (editorInstance.EditorWindow.parent.FCKBrowserInfo.IsIE)
    {
        return range.htmlText;
    }
    else
    {
        var clonedSelection = range.cloneContents();
        var div = document.createElement('div');
        div.appendChild(clonedSelection);
        return div.innerHTML;
    }
}