Q:

How to auto poweroff after Ubiquity preseed install of Ubuntu desktop

I have remastered a normal desktop amd64 iso you can officially download.
With the following contents of isolinux/isolinux.cfg the preseed works fine:
default live
        label live
          menu label ^Start Kubuntu
          kernel /casper/vmlinuz.efi
          append  file=/cdrom/preseed/kubuntu.seed boot=casper noninteractive initrd=/casper/initrd.lz quiet splash --

but in the end the preseeded poweroff (d-i debian-installer/exit/poweroff boolean true) does not take place, instead when the installer is finished the Desktop session is started. 
I have tried setting various combinations of the following preseed options, but it always starts the Desktop session in the end:
d-i finish-install/reboot_in_progress note
d-i debian-installer/exit/halt boolean true
d-i debian-installer/exit/poweroff boolean true

Info: I have inserted all preseed lines in preseed/kubuntu.seed

A:

Okay I have found the solution, the following keys solve the problem:
  ubiquity ubiquity/reboot boolean true
  ubiquity ubiquity/poweroff boolean true

