Using drupal's webform_token module to replace values of confirmation message. e.q: Congratulations, [webform:val-salutation]. [webform:val-last_name]

gistfile1.php

function hook_preprocess_webform_confirmation(&$vars) {
  module_load_include('inc', 'webform', 'includes/webform.submissions');

  $node = $vars['node'];
  $webform = $node->webform;
  $submission = webform_get_submission($node->nid, $vars["sid"]);
  $confirmation = $node->webform['confirmation'];
  $confirmation = token_replace($confirmation, array('webform' => $submission), array('webform_tokens'));
  $vars['confirmation_message'] = $confirmation;  

}