Replace textfield value on ajax callback

Question

1) Am i missing something here? it's not replacing the textfield value.
2) Also how do i replace if i have a multiple textfield and multiple button in a form.

<?php
    function test($form, &$form_state) {
      if (isset($form_state['values']['your_name'])) {
        $name_value = $form_state['values']['your_name'];
      }
      else {
        $name_value = "";
      }

      $form = array();
      $form['your_name'] = array(
        '#title' => t('Your or your company name'),
        '#type' => 'textfield',
        '#value' => $name_value,
        '#prefix' => '<div id ="subscribers-name">',
        '#suffix' => '</div>',
      );
      $form['load_settings'] = array(
        '#type' => 'button',
        '#value' => t('Load my settings'),
        '#ajax' => array(
          'wrapper' => 'subscribers-name',
          'callback' => 'simplenews_mod_load_subscriptions_ajax',
          'method' => 'replace',
        )
      );
      return $form;
    }

    function simplenews_mod_load_subscriptions_ajax($form, &$form_state) {
      $form_state['values']['your_name'] = "loaded value";
      return $form['your_name'];
    }

Answer 1

function test($form, &$form_state) {
  $form['your_name'] = array(
    '#title' => t('Your or your company name'),
    '#type' => 'textfield',
    '#prefix' => '<div id ="subscribers-name">',
    '#suffix' => '</div>',
  );
  if (isset($form_state['values']['your_name'])) {
    $form['your_name']['#value'] = 'if';
  }
  else {
    $form['your_name']['#value'] = 'else';
  }
  $form['load_settings'] = array(
    '#type' => 'button',
    '#value' => t('Load my settings'),
    '#submit' => 'simplenews_mod_load_subscriptions',
    '#ajax' => array(
      'wrapper' => 'subscribers-name',
      'callback' => 'simplenews_mod_load_subscriptions_ajax',
      'method' => 'replace',
    )
  );
  return $form;
}

function simplenews_mod_load_subscriptions_ajax($form, &$form_state) {
  return $form['your_name'];
}