DTNX Postmaster:
I suspect this is a problem with either your configuration, or your TLS stack. Exchange 2010 should do better, even in it's default configuration, as the minimum OS stack is Windows Server 2008, which supports TLSv1 with the 'ECDHE-RSA-AES128-SHA' cipher if the relay server supports it.
that's the point. the TLS stack used by the submission server isn't brand new ...
Andreas
