I checked the log in /tmp/smscon.log in my - post theft recovered n900 (full story here) - to realize it was extremely short with hardly any logs.

Could it be that the log file is erased with every phone or deamon restart?

If this is true I think it would be a good idea to keep all smscon logs and maybe even give the option to send it pair e-mail or upload it somewhere as a file etc.)