VZW + Outlook2003 + SMTPS? MTU? Proxy?

Greetings,

Has anyone encountered

  Mar 17 14:24:01 mail postfix/smtpd[32452]: SSL_accept
  error from unknown[166.154.120.211]: -1

  Mar 17 14:24:01 mail postfix/smtpd[32452]: warning: Write
  failed in network_biopair_interop with errno=32:
  num_write=-1, provided=974

or similar using Outlook 2003 and SMTPS? Outlook reports a
connection timeout, though Postfix obviously is seeing packets.
I'm trying to determine why Outlook thinks Postfix isn't there,
and why Postfix thinks the SSL negotiation was aborted.

The op content: I'm asking in particular if any proxying[*], MTU
issues, or other network creativity is known on the VZW network.
PMTUd works on the Postfix end.

I don't have the VZW-connected machine handy ATM to test further.
SMTPS on that machine works correctly on non-VZW providers. I
don't know about HTTPS, so I admittedly can't rule out PKI fun.

[*] Yes, I know it would be foolish and futile to try proxying
    TCP/465 at the app level.

Eddy