Same CCK field in different features (with different widget settings) causes problems

I can provide some simple code (for the maintainers of the Features module) to switch between different cases when adding a CCK field via Features module.
The code is a modification of different code that I found at Drupal.org. I used the code for my own "CCK-definitions-in-code"-import module, but Features module is much better!!!
Maybe this can be a starting point to solve this issue:

/**
 * Create a new field or add an existing field for an existing content type.
 *
 * @param $content_type
 *   Required. Existing content type (text id).
 * @param $field_name
 *   Required. A field name using only alpha-numeric and underscores.
 * @param $field_widget_type
 *   Required. A special name that uniquely identifies both the field type and
 *   widget type. Each option item on the first page of the 'Add Field' form.
 * @param $label
 *   Required. Label of the CCK field.
 * @param $properties
 *   Optional. An array of additional properties for the field.
 */
function myfunc_create_or_add_existing_field($content_type, $field_name, $field_widget_type, $label, $properties = array()) {
  module_load_include('inc', 'content', 'includes/content.admin');
  module_load_include('inc', 'content', 'includes/content.crud');

  $content_fields = content_fields();
  $content_types = content_types($content_type);
  if (!isset($content_types['fields'][$field_name])) {
    // Not existing CCK field in content type.
    if (!isset($content_fields[$field_name])) {
      // Create new CCK field.
      myfunc_create_field($content_type, $field_name, $field_widget_type, $label, $properties); // FEATURES must put its own function here!!!!
    }
    else {
      // Add existing CCK field to content type.
      myfunc_add_existing_field($content_type, $field_name, $field_widget_type, $label); // FEATURES must put its own function here!!!! - AND this is the place which seems to be missing in FEATURES at the moment, because here only a new 'content_node_field_instance' entry (= a new widget for another content type) will be created.
    }
  }
  else {
    // Already existing CCK field in content type.
    // NOTHING happens here in my use case, but maybe this is the place for a FEATURES callback to update an existing CCK field!!!
  }
}

Does anybody know how CCK fields are "imported" by Features module?
Do they a) live in code (at runtime) or is there b) a physical import into the database.
I don't have the time to dive into Features module's code, but I think that b) is the right answer.
Then the next question would be: Does Features module use some API functions of Content (CCK) module or are there own CCK import functions in Features module.

To solve this issue we must find the place where the switch (see #2) must be included...
(and maybe we need some additional code to handle the case "Add existing CCK field to content type.")

Thanks yhahn!

In my own approach I use drupal_execute() to create my CCK fields from my CCK field settings code (it differs a little bit from what you get by using CCK export functionality).

Going this way I get the wanted behaviour that there is no difference between the creation of a CCK field manually (via UI) and the creation of a CCK field with my own import logic.
Especially the case "existing CCK field for a new content type" (which is causing the trouble in Features module) works well with my approach.

Do we have a CCK expert here who is familar with CCK API functions? I don't have the time to become such a CCK expert right now...

Like said before: I like Features module and I am interestend in a working CCK import inside Features module.

Where is our CCK guru to solve this issue?

A starting point for some research could be 'Manage fields' form at content type settings (admin UI): http://drupalcontrib.org/api/function/content_field_overview_form/6
I think that comparing the 'manual way' of CCK field creation (or update) via admin UI with the 'automated way' in Features module is the key to find a solution.

The relevant function inside Features module should be: http://drupalcontrib.org/api/function/content_features_rebuild/6
Right?

And this is the code that I used as basis for my own CCK import functionality (which is working fine, but I like Features module UI...)
http://drupalcontrib.org/api/drupal/contributions--install_profile_api--...
There is a content_field_edit_form_submit (http://drupalcontrib.org/api/function/content_field_edit_form_submit/6) call at the end of install_create_field function which is not included in content_features_rebuild function inside Features module (see above). Could this be the reason???

Enough for today. Maybe someone helps me, diving into this issue...

@David:
Thank you for your patch.
I will test it in the next days and report back here...

For me it seems to work properly, too. Changed status to rtbc.

@David: Thanks again.