Accessing parts of a message with IMAP

[William Wyatt <[e-mail]>]

I have a question regarding how to access various parts of a message
with IMAP.  The easiest way to pose the question is with an example.
Below is an example message followed by some FETCH commands and what I
expect to get back
from each one.  I would appreciate any and all feedback regarding the
validity (or invalidity) of my interpretation of the FETCH command.

Thanks,
William J. Wyatt
Boston Technology, Inc.
[e-mail]
508 738 3147

Here is the example message followed by my FETCH commands.

From: [e-mail]
To: [e-mail]
Date: 08/29/97 09:43:23
Subject: An IMAP test.
MIME-Version: 1.0
Content-type: multipart/mixed; boundary=unique-boundary-1
<blank line>
--unique-boundary-1
Content-type: audio/x-bti-oki24
<blank line>
... here is the data ...
<blank line>
--unique-boundary-1
Content-type: message/external-body; access-type=cifs; name="<file
name>"; size=12510
<blank line>
Content-type: audio/x-bti-oki24
Content-ID: <some id>
<blank line>
<blank line>
--unique-boundary-1

Ok.  I want to fetch various parts of body part 1 (aka MIME entity 1).
This is what I expect given my interpretation of the description of the
FETCH command in RFC 2060: (assume this is message 1)

FETCH 1 BODY[HEADER] gives me:
From: [e-mail]
To: [e-mail]
Date: 08/29/97 09:43:23
Subject: An IMAP test.
MIME-Version: 1.0
Content-type: multipart/mixed; boundary=unique-boundary-1

FETCH 1 BODY[TEXT] gives me:
--unique-boundary-1
Content-type: audio/x-bti-oki24
<blank line>
... here is the data ...
<blank line>
--unique-boundary-1
Content-type: message/external-body; access-type=cifs; name="<file
name>"; size=12510
<blank line>
Content-type: audio/x-bti-oki24
Content-ID: <some id>
<blank line>
<blank line>
--unique-boundary-1

FETCH 1 BODY[1] gives me:
Content-type: audio/x-bti-oki24
<blank line>
... here is the data ...

FETCH 1 BODY[1.MIME] gives me:
Content-type: audio/x-bti-oki24

FETCH 1 BODY[2] gives me:
Content-type: message/external-body; access-type=cifs; name="<file
name>"; size=12510
<blank line>
Content-type: audio/x-bti-oki24
Content-ID: <some id>
<blank line>
<blank line>

FETCH 1 BODY[2.MIME] gives me:
Content-type: message/external-body; access-type=cifs; name="<file
name>"; size=12510

FETCH 1 BODY[2.HEADER] gives me:
Content-type: audio/x-bti-oki24
Content-ID: <some id>

and,

FETCH 1 BODY[2.TEXT] returns nothing (or an error?) since the 'text' for
this is external.
I would also assume that if this MIME entity had a content-type of
message/rfc822 instead of
message/external-body that FETCH 1 BODY[2.TEXT] would return me the
text/data portion of
the encapsulated rfc822 message.