It seems you didn't understand me. I did some more experiments and discovered that I can use word "default" everywhere when "select" or "multiselect" is expected. Here is preseed.cfg I ended up with: https://paste.debian.net/hidden/2a058f0e/ . Especially see this lines:
d-i keyboard-configuration/xkb-keymap default d-i apt-setup/services-select default tasksel tasksel/first default It seems that in all these cases default option/options are selected. It is very cool! I like this feature. Is it supposed to work or does it work by accident? Please, document it. Reopening bug. > Holger -- Askar Safin