The Apostrophe Conversion Problem

Hi there,

I have set in the config.js as below,

CKEDITOR.editorConfig = function( config ) {

    config.toolbarGroups = [
        { name: 'clipboard',   groups: [ 'clipboard', 'undo' ] },
        { name: 'editing',     groups: [ 'find', 'selection', 'spellchecker' ] },
        { name: 'links' },
        { name: 'insert' },
        { name: 'forms' },
        { name: 'tools' },
        { name: 'document',       groups: [ 'mode', 'document', 'doctools' ] },
        { name: 'others' },
        '/',
        { name: 'basicstyles', groups: [ 'basicstyles', 'cleanup' ] },
        { name: 'paragraph',   groups: [ 'list', 'indent', 'blocks', 'align', 'bidi' ] },
        { name: 'styles' },
        { name: 'colors' },
        { name: 'about' }
    ];

    config.removeButtons = 'Underline,Subscript,Superscript';
    config.format_tags = 'p;h1;h2;h3;pre';
    config.removeDialogTabs = 'image:advanced;link:advanced';
    
    config.entities_additional = '';
};

My problem is that how do I prevent the automatic conversion of apostrophe ' become ';

Thanks,