В общем, одно вложение уходит идеально, со вторым проблема, его просто не видно.
Вот сурс:
<?php
$boundary ="=_".md5(uniqid(time()));
$boundary2="=_".md5(uniqid(time()+1500));
$headers="MIME-Version: 1.0\\n";
$headers.="Content-Type: multipart/mixed;\\n";
$headers.=" boundary=\\"".$boundary."\\"\\n";
$headers.=" boundary2=\\"".$boundary2."\\"\\n";
$headers.="X-Priority: 3\\n";
$headers.="X-Mailer: PHP/" . phpversion()."\\n\\n";
$body ="\\nThis is a multi-part in MIME format.\\n\\n";
$body.="--".$boundary."\\n ";
$body.="Content-Type: multipart/alternative;\\n";
$body.=" boundary=\\"".$boundary."\\"\\n\\n";
$body.=convert_cyr_string("** Это содержимое письма **\\n","w","k");
$body.="--".$boundary."\\n";
$body.="Content-Type: text/html;\\n";
$body.=" name=\\"a.html\\"\\n";
$body.="Content-Transfer-Encoding: base64\\n";
$body.="Content-Disposition: attachment;\\n";
$body.=" filename=\\"a.html\\"\\n\\n";
$body.=chunk_split(base64_encode("Проверка отправки аттача"))."\\n";
$body.= "--".$boundary. "--\\n";
$body.="--".$boundary2."\\n";
$body.="Content-Type: text/html;\\n";
$body.=" name=\\"b_bla.html\\"\\n";
$body.="Content-Transfer-Encoding: base64\\n";
$body.="Content-Disposition: attachment;\\n";
$body.=" filename=\\"b_bla.html\\"\\n\\n";
$body.=chunk_split(base64_encode("Проверка намбер два отправки аттача"))."\\n";
$body.= "--".$boundary2. "--\\n";
mail("test@dj-shop.ru", convert_cyr_string("this_is_subj","w","k"), $body, "From: [email]info@dj-shop.ru[/email]\\n".$headers);
?>