[Mailman-Users] No "welcome" or "results" messages

[Douglas Marmon]

I have established a read-only mailing list using Mailman 2.1.2.
I do not want members to post or deal with passwords or options.
I do not send any welcome message or good-bye message.
Just subscribe and unsubscribe with confirmation.
The only email the members should see is
    confirm subscription
    ... messages posted by list-owner ...
    confirm unsubscription

I have built a web-page for them to enter an email address, then click a
subscribe or unsubscribe button. Mail is sent to -request with the subscribe
or unsubscribe command.
An email confirmation is sent to the member.
He replies to the email confirmation.
He receives a message of "Results of your email commands" which says that
the confirmation worked but the rest of the message was "unprocessed". I
don't think this is a useful message and would like to stop it.
Something similar happens at unsubscribe.

How can I stop these extra "results" messages?