[squid-users] Samba domain and ntlm_auth, seamless auth NOT wanted

Hello,
I successfully configured squid 2.5 as a proxy for Internet access inside
a LAN where a Samba domain is used.
I used ntlm_auth and winbind on the proxy machine, so users opening
Explorer on Windows clients are authenticated against the Samba user
database on the PDC.

Everything runs smoothly... just a bit TOO smoothly: when a user is
already logged in on the domain, Explorer just uses his username and
password, without asking him anything. Instead, I would prefer that a
requester asking for username and password pops up each time they start a
browsing session, even if they have to re-type the same data they used to
login (I do not want to give them a second password to remember).

I'd prefer this to make users more aware of the fact that their Internet
access is being logged (they will be warned anyway before starting all
this, but you know how easily users forget...), and to protect them from
other users who might use Explorer while they leave their PC alone with
their user logged in.

Is this currently possible, somehow?
Thanks.

-- 
Ciao,
  Marco.
..."Refugee", Refugee (1974)