htaccess file in callback folder has:
php_value auto_prepend_file none
php_value auto_append_file none
ie. files in this folder are not put on design.
However, the files in callback folder is being put design on by the htaccess file from the www folder, this did not happen on apache.
it seems like the htaccess file located in the callback folder has no effect as soon htaccess file from the www folder is loaded