PPPoE statistic

Wed Nov 1 06:55:29 UTC 2006

I have gateway with FreeeBSD 6.0 and LAN users get access to Internet through pppoe connection. I can see connection statistic when it alive

# pppctl /var/tmp/pppuser3 ! echo UPTIME USER OCTETSIN OCTETSOUT
1:28:46 drgho 148957 504786

but I want to colect this information exactly before conection down.
Can I put this command or samething else in ppp.linkdown for this purpose?