CKEditor ID - how do I get this?

With FCKEditor 2.x. I can set editor css like this:

   fckeditorInstance.EditorDocument.body.style.cssText += 'background-color: #FFFFFF;' ;

EditorDocument is not a valid object in CKEditor 3.1, but according to the docs, I should be able to change CSS on the fly like this:

var element = CKEDITOR.dom.element.getById( 'myElement' );
element.setStyle( 'background-color', '#ff0000' );

When this is called, I get an "'element' undefined" error.

I've also tried grabbing the editor ID with these:

var element = new CKEDITOR.dom.element( document.getElementById( 'comments' ) );
var element = CKEDITOR.document.getById( 'comments' );

These also generate 'element' undefined errors.

The myElement text box was created with this:

(via PHP API)
   $config = array();
   $config['toolbar'] = array( array( 'Bold', 'Italic', 'Underline', 'Strike', '-', 'Source' )   );
   
   $CKEditor                      = new CKeditor() ;
   $CKEditor->basePath             = '/includes/ckeditor/' ;
   $CKEditor->returnOutput          = true;
   $CKEditor->config['skin']          = 'v2';
   $CKEditor->config['height']       = 150;
   $CKEditor->config['width']          = 400;
   $CKEditor->config['resize_enabled'] = false;
   $html_input_comments            = $CKEditor->editor('myElement', $mySavedData, $config, $events);

I don't know what else to try.

Developers, could you please lend a hand? Kind thanks.