How to set label for combo plugin?

var FCKDropdownBox = function( name )
{
   this.Name = name ; 
}

FCKDropdownBox.prototype.Execute = function( itemClass, itemLabel )
{ 
   var style = new FCKStyle( itemClass ) ;
   style.Label = itemLabel.innerHTML ; // that's the name of the label
   
   if ( typeof style == 'string' )
      style = this.GetStyles()[ style ] ;
   
   if ( style )
   {
      if ( style.GetType() == FCK_STYLE_OBJECT )
         style.ApplyToObject( FCKSelection.GetSelectedElement() ) ;
      else
         style.ApplyToSelection( FCK.EditorWindow ) ;
      
      FCKUndo.SaveUndoStep() ;
      FCK.Events.FireEvent( 'OnSelectionChange' ) ;
      this.SetLabel( style.Label ) ; // try to set the selected label, but I get [object Object]
   } 

   //if ( style.IsActive )
   //   FCKStyles.RemoveStyle( style.Name ) ;
};

FCKDropdownBox.prototype.GetState = function()
{
   return;
};

FCKCommands.RegisterCommand( 'StyleCombo' , new FCKDropdownBox() ) ; 

var FCKToolbarStylesCombo = function( tooltip, style )
{
   this.Command = FCKCommands.GetCommand( 'StyleCombo' ) ;
   this.CommandName = 'StyleCombo' ;
   this.Label = this.GetLabel() ;
   this.Tooltip = tooltip?tooltip:this.Label ;
   this.Style = style ;
};

FCKToolbarStylesCombo.prototype = new FCKToolbarSpecialCombo ;

FCKToolbarStylesCombo.prototype.GetLabel = function()
{
   return 'Style' ;
};

FCKToolbarStylesCombo.prototype.CreateItems = function()
{      
   var stylesXmlPath = FCKConfig.StyleComboXmlPath ;

   // Load the XML file into a FCKXml object.
   var xml = new FCKXml() ;
   xml.LoadUrl( stylesXmlPath ) ;

   var stylesXmlObj = FCKXml.TransformToObject( xml.SelectSingleNode( 'Styles' ) ) ;

   // Get the "Style" nodes defined in the XML file.
   var styleNodes = stylesXmlObj.$Style ;

   // Add each style to our "Styles" collection.
   for ( var i = 0 ; i < styleNodes.length ; i++ )
   {
      var styleNode = styleNodes[i] ;

      var element = ( styleNode.element || '' ).toLowerCase() ;

      if ( element.length == 0 )
         throw( 'The element name is required. Error loading "' + stylesXmlPath + '"' ) ;

      var styleDef = {
         Element : element,
         Attributes : {}
      } ;

      // Get the attributes defined for the style (if any).
      var attNodes = styleNode.$Attribute || [] ;

      // Add the attributes to the style definition object.
      for ( var j = 0 ; j < attNodes.length ; j++ )
      {
         styleDef.Attributes[ attNodes[j].name ] = attNodes[j].value ;
      }

      // Set styles and labels to the dropdown
      this._Combo.AddItem( styleDef, styleNode.name ) ;
   }
}

FCKToolbarItems.RegisterItem( 'StyleCombo', new FCKToolbarStylesCombo( 'StyleCombo', FCK_TOOLBARITEM_ICONTEXT ) ) ;