Comment 3 for bug 44609

This also/still affects Hardy, but there is a work-around.

First, once the Live CD has started, open a terminal and run:

sudo su
sed -i 's,^\( *grep -v '^/dev/md' |\),#\1,' /lib/partman/init.d/30parted | grep '/dev/md'

This will allow Ubiquity's partman to report /dev/md* devices by commenting out the script statement that ignores them.

Next, manually install a file-system to the md device. E.g:

sudo mkfs.ext3 -L boot /dev/md0

Now when Ubiquity's partman runs in manual mode you'll see something like this in the partition list:

/dev/md0
  /dev/md0 ext3 256 MB 14 MB

Select the indented /dev/md0, press the "Edit partition" button, set the file-system type to ext3, tick the Format check-box, and set the mount-point.

Ubiquity/partman will now successfully format and install to /dev/md0 when the install is started.