ahah_helper_render unable to handle changes of ahah properties on the same field

First, thanks for your code, which is without doubt a great saving in terms of effort and time, and sorry in advance for my bad English.
I found that the code of ahah_helper_render is unable to handle the case of changes to the ahah properties (i.e. the event) on the same field.
Take the case where we want a field is represented with an autocomplete textbox when the value is not in a certain range, or with a selectbox when the interval is defined.
In the first case we will use a textbox autocomplete and an event type blur. In the second, a combobox with an event change.
Please note that the field that is changed has always the same name and id. In the sample code below has been the case described:

if ($my_range_value != '') {            
            $options =get_options_for_my_range($my_range_value);
            $form['my_wrapper']['myrange'] = array(
                    '#type' => 'select',
                    '#title' => t('The Range'),
                    '#default_value' => $my_range_value,
                    '#options' => $options,
                    '#required' => TRUE,                    
                    '#ahah' => array(
                            'event'=>'change',
                            'wrapper' => 'my-wrapper',
                            'path'=>ahah_helper_path(array('my_wrapper')),
                            'method' => 'replace',
                    ),
                    
            );             
        } else {
            $form['my_wrapper']['myrange'] = array(                   
                    '#type' => 'textfield',
                    '#title' => t('The Range'),
                    '#default_value' => $my_range_value,
                    '#autocomplete_path' => 'my_range/autocomplete',
                    '#required'=>TRUE,
                    '#ahah' => array(
                            'event'=>'blur',
                            'wrapper' => 'my-wrapper',
                            'path'=>ahah_helper_path(array('my_wrapper')),
                            'method' => 'replace',                    
                ),
            );            
        }

When the textfield with an ahah event of type "blur" is dynamically replaced in the form with a selectbox with an ahah event of type "change", Drupal.settings is not updated with data from the new element: infact, the code in the function ahah_helper_render generate a json vector with settings data using the previous layout of the form:

  // Get the JS settings so we can merge them.
  $javascript = drupal_add_js(NULL, NULL, 'header');  
  $settings = call_user_func_array('array_merge_recursive', $javascript['setting']);

  drupal_json(array(
    'status'   => TRUE,
    'data'     => theme('status_messages') . drupal_render($form_item),
    'settings' => array('ahah' => $settings['ahah']),
  ));

The first solution I've found to solve this problem was to slightly modify the function ahah_helper_render, adding the code that was able to read the new field structure with ahah attribute and eventually to merge the changes to the settings array.
I know that this is a partial solution, because it doesn't care of nested form elements. Improvements are welcome!

Check the attached patch file.