Disable SCAYT from within a plugin

I would like to enable and disable SCAYT from within a plugin. According to the FCKeditor documentation, it's possible to  disable a plugin using:

oEditor.EditorWindow.parent.FCKToolbarItems.LoadedItems[commandName].Disable();

(See: http://docs.cksource.com/FCKeditor_2.x/Developers_Guide/JavaScript_API)

However, I can't get EditorWindow using oEditor.

Thanks.