Templates attach static file

Hello,
I have a Template and i would like to attach a file to it, but the file is not in RT it ist in /tmp/test.xlsx
is there an Mail or RT tag, like RT-Attach: /tmp/test.xlsx?

To: Me@there.com
Subject: Testmail
RT-Attach-Message: yes

Testmail

RT 4.4.1 on Ubuntu 16.04