[[response.php]]
@DIV
<?
header( "Content-Type: text/html; Charset=utf-8" );
header( "pragma: no-cache" );
header( "Expires: Wed, 31 May 2000 14:59:58 GMT" );
header( "Cache-control: no-cache" );

mb_language( "ja" );
mb_internal_encoding("UTF-8");

// Windows 用として CRLF
$text .= $_GET['fld1']."\r\n";
$text .= $_GET['fld2']."\r\n";

$utf8 = $text;

// 書き込みは Windows 用として SHIFT_JIS
$text = mb_convert_encoding( $text, "SHIFT_JIS", "UTF-8" );

file_put_contents( $_GET['fld1'].".txt", $text );

// Flex は utf-8 なので、変換前を返す
print_r($utf8);
?>
@END

http://logicalerror.seesaa.net/article/197722171.html(Flex4 : HTTPService で入力データを PHP に送る)