E-Mail Append to

Hallo,
i have an external pop to communicate over the system.
Inside an issue (below all infos), where i can make a comment, i also can make an e-mail - e.g. to the customer. That works in both directions, because in mail-config i appended this mail-address to the issue. If the customer (extern) answers, i can see his answer-mail also below the infos inside the issue.
fine - classical support-ticket-functionality.

Now i checked the same procedure inside a task!
It does not work. Outgoing ok, but a simple answer does not arrive.
Ok, i thought i have to make a new e-mail-account.I set up a new pop and startet to setup a new e-mail account inside erpnext.

But: in the field “append to” i cannot take a “task”. It is not there in the list.

so my question - how to setup, that mails, sendet out of a task, also could be answered and arrive inside the task.

thanks.

Hallo,
no solution or workaround for this?

I can bind a incoming email (append) to an issue, event, communication, job applicant, opportunity.
But i want to use it as a task!

How i could make this happen?

Thanks for help.