An image when a trap is logged

hello
I’m french and i hope you’ll forgive me for my bad english.
I wrote a little perl script which writes a line in nagios.log file. As a result, i can see that on event log page:
[07-15-2009 10:09:08] TRAP RECU le Wed Jul 15 2009 a 10:09:07 pour l equipement localhost (127.0.0.1) --> upsBatteryNeedsReplacement

and just before there is a blue-circled i, and i wish to change this image when a trap is logged.
how can i do it?

the best way, i found is adding existing string like that:
SERVICE ALERT: localhost;extremePowerSupplyFail;CRITICAL; my text

other ideas?