To use automatic reply instead of double opt-in

Hallo, I’m using an autoresponder plugin to send an automatic message when people subscribes.
It will/should work like this:

  1. You add your email on the main form choosing your list.
  2. You receive the welcome message.
  3. You reply to the welcome message to confirm your identity, no need to click a confirmation link, so you will just receive the automatic reply with the first information you need, depending on the choosen list.

If I don’t disable the double opt-in, every users shall need to reply to the last welcome message, to receive the automatic reply. This automatic reply is the main purpose for what I’m doing.

Any suggestion?