Thanks @piper
Installation worked fine, but i'm struggeling now with this bad boy:
Das installierte System sollte eine Kernel-Befehlszeile mit folgenden Optionen aufweisen (UUID wird benutzt):
root=/dev/mapper/cryptroot cryptopts=source=UUID=12345678-1234-1234-1234-1234567890AB,target=cryptroot
Because after the installation worked out, i just tried to restart and (of course) no bootable device was found. How do I proceed? Is this line here
root=/dev/mapper/cryptroot cryptopts=source=UUID=12345678-1234-1234-1234-1234567890AB,target=cryptroot
something, that should go into /etc/default/grub? And if yes, is this even the "right" file, when I boot the live cd? I'm very confused here ...