Just a thought, it might be worth trying Resource Manager Essentials (RME). Both 3.5 & 4 should support the FWSM with the lastest IDUs.
It can be a bit of a pain to setup though, you nnormally eed to enable an SNMP read string on the device in order to import it into RME for syslog analysis.
However, I recently setup logging to RME with VPN Concentrators, which works pretty well (quite easy to filter and view messages).
In general though Checkpoint and ISA 2004 logging is much easier to work with.
An example RME link below:
http://cio.cisco.com/univercd/cc/td/doc/product/rtrmgmt/cw2000/cw2000e/e_3_x/3_5/e3_5.htm