Finally, got it to work. Add this in functions.php:
add_action('wp_enqueue_scripts','aahank_register_script');
function aahank_register_script(){
//Re-register quicktags script
wp_deregister_script('quicktags');
wp_register_script('quicktags', 'http://static-content.com/wp-includes/js/quicktags.js', false, false, true);
wp_localize_script( 'quicktags', 'quicktagsL10n', array(
'wordLookup' => __('Enter a word to look up:'),
'dictionaryLookup' => esc_attr(__('Dictionary lookup')),
'lookup' => esc_attr(__('lookup')),
'closeAllOpenTags' => esc_attr(__('Close all open tags')),
'closeTags' => esc_attr(__('close tags')),
'enterURL' => __('Enter the URL'),
'enterImageURL' => __('Enter the URL of the image'),
'enterImageDescription' => __('Enter a description of the image'),
'fullscreen' => __('fullscreen'),
'toggleFullscreen' => esc_attr( __('Toggle fullscreen mode') ),
'textdirection' => esc_attr( __('text direction') ),
'toggleTextdirection' => esc_attr( __('Toggle Editor Text Direction') )
));
}
As for the code used in wp_localize_script, I got it straight from source: http://core.svn.wordpress.org/trunk/wp-includes/media.php