title: MIME "multipart/related" Structure and Apple Mail. Is it a Bug?
body: <p>I build a E-Mail with PHP Zend Framework Class <strong>Zend_Mail</strong>. There is one text- and one html-part with related inline-images. I want to attach one pdf-file too.</p>
  
  <p>My question is about the mime-structure. Two options are possible:</p>
  
  <p>option 1:</p>
  
  <pre><code>Content-Type: multipart/mixed
    Content-Type: multipart/alternative 
      Content-Type: text/plain; charset=UTF-8      
      Content-Type: multipart/related 
        Content-Type: text/html; charset=UTF-8 
        Content-Type: image/jpeg
        Content-Type: image/jpeg
        Content-Type: image/png
    Content-Type: application/pdf 
  </code></pre>
  
  <p>option 2:</p>
  
  <pre><code>Content-Type: multipart/related;
    Content-Type: multipart/alternative;
      Content-Type: text/plain; charset=utf-8
      Content-Type: text/html; charset=utf-8
    Content-Type: image/jpeg
    Content-Type: image/jpeg
    Content-Type: image/png
    Content-Type: application/pdf
  </code></pre>
  
  <p>option 2 is built by Zend_Mail, but the pdf is not recognized at Apple Mail Application. It's fine in Thunderbird 3 and Outlook 2007. Only in Apple Mail the PDF-Attachment isn't recognized. </p>
  
  <p>option 1 is ok in Apple Mail, Thunderbord and Outlook. But it would be a little bit tricky to get this structure out of the Zend Framework Class <strong>Zend_Mail</strong>.</p>
  
  <p>Is this a Bug in Apple Mail or is option 2 not normative?</p>
  
  <p>kind regards,
  sn</p>