[etc]

Ну вот, что надумалось:

sr.clonen.onChanged = function() {
     var index = Selection.getCaretIndex();
     var broken = this.text.split(chr(4));
     for (var i = 1; i<broken.length; i++) {
          broken[i] = String.fromCharCode(1024+broken[i].charCodeAt(0))+broken[i].substr(1);
     }
     var out = broken.join("");
     if (index<out.length-1&&this.text.length!=out.length) {
          Selection.setSelection(index-1,index-1);
     }
     this.text = out;
};

Опять же, актуально IE only.