Mendelson Opensource AS2 1.1 Build 49 Transmission log

When my partner starts sending larger size file (100+ MB), the time stamp matches between the partner and my server in firewall logs. But AS2 applicatoin is starts writing a log when only after 20 mins of time approximately. Can anyone clarify me where AS2 is storing the data and why it starts writing a log and showing the transmission in application after the specified time of 20 mins...?? It would be more helpful if someone clarified this.

Thanks in Advance.