[erlang-questions] Newbie: at what point should an event handler be installed?

[Schneider]

Hi list,

I have a very basic application with a supervisor started which starts a 
gen_fsm which handles some serial line data and a gen_event process 
which should log some of the serial line data to a mnesia table. I want 
to implement the logging to the mnesia table as an event handler. At 
what point does one install the event handler using gen_event:add_handler.
Logging to the database is always on, but logging to the terminal is 
optional.
Installing the handler at the application level after starting the 
supervisor works but does not feel right, nor does the supervisor.
Could you give me some advice?
Thanks.

Frans