override background color inherited from stylesheet

I've just upgraded from 2.2 to 2.5b . I'm having problems overriding the editors background color.

I set the editor to use the default stylesheet for my website;

oFCKeditor.Config[ "EditorAreaCSS" ] = '/standard.css' ;

In 2.2 I then override any background color settings in the stylesheet by calling the following javascript using the FCKeditor_OnComplete event handler;

var editor_frame = document.getElementById(thisEditor.Name+"___Frame");
var editor_source = editor_frame.contentWindow.document.getElementById("eEditorArea");
editor_source.contentWindow.document.body.style.backgroundColor = '#00ffff;
editor_source.contentWindow.document.body.style.backgroundImage='none';

In 2.5 i can see that the "eEditorArea" iframe has been replaced by and empty cell "xEditingArea". I've played around quite a bit with this but cannot ovverride settings in the external stylesheet.

If no external stylesheet is set then the following works, but is not a solution to this problem:

oEditor.EditorDocument.body.style.cssText += 'background-color: #00ffff;' ;

HELP !