Drupal Pagebreak button not showing

Hello, I have a problem with DrupalPageBreak button, it not appear, but DrupalBreak button (teaser) appears on toolbar. I`ve found this problem in 6.x-1.5 version, then I`ve installed 6.x-dev version (2011-Jul-19), but still have the same problem. Both plugins switched on in the CKEditor profile for current role. I`ve tried to debug this issue and found that 'Drupal.settings.ckeditor.pagebreak' variable is undefined in 'if' statement in the line 46 of 'ckeditor\plugins\drupalbreaks\plugin.js' file. If I comment this line and also comment the closing braсket in line 53, DrupalPageBreak button appears on toolbar.

			//if ( Drupal.settings.ckeditor.pagebreak ) {
				editor.ui.addButton( 'DrupalPageBreak',
						{
							label : Drupal.t( 'Insert Page Break' ),
							icon : this.path + 'images/drupalpagebreak.png',
							command : 'drupalpagebreak'
						});
			//}