Comment 80 for bug 568050

(Postet originally to Mint's buglist by me, but in case it can help someone, I copy-paste it here)

Finaly, after many hours I came to a workaround that actually works. To anyone interested:
1) Boot with a previous version that works (ex Karmic) and create the desired partitions
2) Boot with Lucid and start installation. Format the partition and set mount point, but do NOT create-delete any partitions.
3) At the last step, choose "Advanced" and select "do not install bootloader". (It wouldn't install anyway, no matter what you choose it just tries to install on /dev/sda).
4) Installation will finish, but do not restart. Open a terminal and let's chroot into our fresh installation.

sudo mkdir /mnt/root
sudo mount /dev/mapper/isw_jfighfbah_My_RAID3 /mnt/root
sudo mount --bind /dev /mnt/root/dev
sudo mount -t proc proc /mnt/root/proc
sudo mount -t sysfs sys /mnt/root/sys
sudo mount -t devpts devpts /mnt/root/dev/pts
sudo cp /etc/resolv.conf /mnt/root/etc/resolv.conf
sudo chroot /mnt/root /bin/bash

now there's the key:

ls /dev/mapper

returns corrects results:
 /dev/mapper/isw_jfighfbah_My_RAID
 /dev/mapper/isw_jfighfbah_My_RAID1
 /dev/mapper/isw_jfighfbah_My_RAID3
...

But if you try to execute

grub-install /dev/mapper/isw_jfighfbah_My_RAID

it will fail. (Aaargh I almost smashed the computer with this one..) I finaly discovered that although we can mount and chroot into the installation, not everything is OK with initrd image and dmraid. So, let's create the image again:

apt-get purge dmraid
apt-get install dmraid
grub-install /dev/mapper/isw_jfighfbah_My_RAID
update-grub

You have now a perfectly working fresh installation of Mint 9 or Ubuntu 10.04 ;)

Hope I've helped in any way...