Redirect directives in virtual host container

[joosty]

In every virtual host container (any user any domain) the following lines exist:

Redirect 301 /webmail      http://<my-ip>/squirrelmail
Redirect 301 /phpmyadmin   http://<my-ip>/phpmyadmin
Redirect 301 /phpMyAdmin   http://<my-ip>/phpMyAdmin
Redirect 301 /roundcube    http://<my-ip>/roundcube
Redirect 301 /squirrelmail http://<my-ip>/squirrelmail

I am unable to locate where this is coming from. It is not in the template file "virtual_host2.conf" or "virtual_host.conf". Can anyone help me locate the source of these lines? I'd like to edit them to say 'https' instead of 'http'.

Joost