Can I configure my mail client (or Gmail's web app) to send mail from a plussed address?

Question

If I had the email address [e-mail], I could use a plus sign to generate a virtually unlimited number of alias names that I could use on each service I signed up on. Like [e-mail] -- If I received junk mail with a To: header that included TwitterSpam, I'd know exactly where the sender got my email address.

My question is, if I receive email from one of these plussed addresses and want to reply to it, the reply will contain a From: header with my true, un-plussed address: [e-mail]. Is there any way to configure either my mail client or Gmail's web app to reply from the same address that the message was delivered to, plus sign and all?

Why? The immediate case that comes to mind is one where I sign up for Xyz Company using [e-mail] and then later open a customer service support ticket. Some of these systems send emails to [e-mail] that ask me to reply directly to the email with comments to update the ticket. I don't want to (at best) "reveal" the bare email or (at worst) appear to be a different person that the ticketing system won't be able to track.

Answer 1

That seems like how to do that is described over on the Web Applications StackExchange in this answer, quoted:

Yes. Add it the same way you'd add any other email to send from:

1. Click on Settings in the upper right.
2. Click on Accounts and Import.
3. In the "Send mail as" section click "Add another email address you own".
4. Add the "plus email" and finish the setup.
5. Compose an email and select the custom "plus email" in the From dropdown.