POM: Mirror netboot installer

[arnoproxmox]

For netbootxyz I want to self-host the netboot installers.

For the (Debian) mirror I use POM.

mirror: debian_bookworm_main
    architectures amd64
    architectures all
    base-dir /data/files/ftp/www/linux/debian
    ignore-errors false
    key-path /usr/share/keyrings/debian-archive-bookworm-stable.gpg
    repository deb http://deb.debian.org/debian bookworm main main/installer-amd64 contrib non-free non-free-firmware
    skip-sections debug
    skip-sections games
    sync false
    verify false

Works fine.

Added main/installer-amd64 to mirror the installer. The installers are not downloaded.
What is the correct way to do this?