How to send email alert as email-to-case when case is closed?

Question

I am able to send email alert when case is closed.

But the email alert NOT showing in email messages at case related list:

The email when case closed is marked as 'CASE CLOSED' in email subject:

Basically I want to add email alert when case is closed and send an email to customer that their case has been closed and add the email outbound in case email messages related list.
So, when the customer reply back to a closed email case, the email will be sent back to its related case as inbound email message (customer reply to an 'email-to-case' address)

How to send email alert that act as an outbound email message in case?

Answer 1

You have to add Case Thread Id field in the Subject line of the Email Template.

Once you've added this in the subject line (Close Email Template) it will basically pasre the ref Id in the subject line and it will attach that email to your case.

Answer 2

Looks like you are including the Case Thread Id in the subject already, so replies to the email will get attached back to the case, assuming you are sending it from you email-to-case email address or an alias that points there such as support@xx.com. To do that from an email alert, you need to set up an org-wide email address.

As far as getting the outbound email to show up in the related list, the only hack I'm familiar with is to cc the email-to-case email address, but then it will look like an received email and not a sent email.