Logging dhcrelay, other than redirecting the -d debug option?

I am hoping to find a way to log the activity of the isc dhcrelay service, apart from redirecting it's "-d" debugging output to a file and logrotating it. I need a long-term record of what the service is doing, and I am conditioned to not leave services running in debug mode indefinitely. Is there a more clever solution, or alternately, has anybody run dhcrelay with "-d" for an extended time?

We are running dhcrelay V3.0pl2 in Checkpoint SPLAT (effectively RHEL 5). The package is vendor-supplied and I cannot update it.