The su -l problem

I sent an email a few weeks ago about the actions of su -l and how it
messes up wtmp... I never got a reply, and the problem is still there. Is
anyone fixing this? It's quite annoying, since my 'ac' and 'last' logs are
also messed up because of it...

Thanks,
And here's an output of the problem, again:

13:56 (6470) jobe_at_meriadoc:[~]> w
 1:56PM  up 14 mins, 1 user, load averages: 0.04, 0.03, 0.03
USER             TTY      FROM              LOGIN_at_  IDLE WHAT
jobe             p0       samwise           1:56PM     - w
13:56 (6471) jobe_at_meriadoc:[~]> \su -l freebsd
[deletia]
13:56 (103) freebsd_at_meriadoc:[~]> w
 1:56PM  up 14 mins, 1 user, load averages: 0.03, 0.03, 0.03
USER             TTY      FROM              LOGIN_at_  IDLE WHAT
freebsd          p0       -                 1:56PM     - w
13:56 (104) freebsd_at_meriadoc:[~]> exit
logout
13:56 (6472) jobe_at_meriadoc:[~]> w
 1:56PM  up 15 mins, 1 user, load averages: 0.03, 0.03, 0.03
USER             TTY      FROM              LOGIN_at_  IDLE WHAT
freebsd          p0       -                 1:56PM     - w
13:56 (6473) jobe_at_meriadoc:[~]>