date_repeat_rrule element usage

Hello,

I can't find any clear example of use of form API element "date_repeat_rrule" declared by Date repeat API (Date API 6.x-2.2) module. I can't get RRULE after form submition. May be somebody already used this element, or saw the article with good example, please, let me know.

Form array is:

function mymodule_edit_form(&$form_state)
{
  $form = array();
  
  $form['date'] = array(
    '#type' => 'date_repeat_rrule',
    '#date_format' => ' d M Y',
    '#date_label_position' => 'above',
    '#date_repeat_collapsed' => true,
  );
  
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
    '#weight' => 10,
  );
  
  return $form;
}

but when I submit this form I get $form_state['values'] the following:

    [date] => 
    [INTERVAL] => 1
    [FREQ] => DAILY
    [UNTIL] => Array
        (
            [datetime] => 2008-04-12 00:00:00
            [tz] => 
            [all_day] => 1
            [granularity] => a:3:{i:0;s:4:"year";i:1;s:5:"month";i:2;s:3:"day";}
        )

    [BYMONTH] => Array
        (
            [2] => 2
        )

    [BYMONTHDAY] => Array
        (
            [3] => 3
        )

    [BYDAY] => Array
        (
            [WE] => WE
        )

    [0] => Array
        (
            [datetime] => 2008-02-19 00:00:00
            [tz] => 
            [all_day] => 1
            [granularity] => a:3:{i:0;s:4:"year";i:1;s:5:"month";i:2;s:3:"day";}
        )

    [op] => Save
    [submit] => Save
    [form_build_id] => form-3d8df8b5e1116d3d5a14c03ef9f01848
    [form_token] => 2e32a5518dcf508fa6a128bcf39d3f13
    [form_id] => mymodule_edit_form

There is no RRULE that I can save to database for example. But the parts of it mixed with excepting dates.