Hi,
There is already a wish request to tag the log files with the thread ID number, but I have not done that (yet?) because it has very large code implications. One suggestion is to use RetrieveConverter0 (in 1.4.15) and RetrieveResultConverter0 (in 1.4.16beta) to add logging to you liking. For instance, you could make a log file for each client, using <append "text" to file>. Have a look in the script library of the forum for some ideas.
Marcel