To add onto Matt's comment you can search the delivery log for the last 5 digits of the EML file name to find the specific delivery session for the SMTP session you included above.
So for example, you can see in the SMTP log the following line:
Data transfer succeeded, writing mail to 29520580.eml
You can then search the delivery log for 20580 to isolate the delivery session.
Von See
Technical Support Supervisor
SmarterTools Inc.
(877) 357-6278
www.smartertools.com