Okay, this is further to Move an existing system to LVM on RAID1, but instead of moving an existing system, we are using the LiveCD (not alternate) to install onto LVM on top of RAID1.

• Boot the LiveCD you want to install from (eg 9.10 alpha4 is what I used, there are newer versions out already though).

• Install mdadm and lvm

  :/# apt-get install mdadm lvm2

• If you don't have your raid-array set up yet, do that now. Instructions in Move an existing system to LVM on RAID1. Also set up the lvm array.

• If you have the array set up,

  :/# mdadm --assemble --scan

  to set it up.

• If you like, you can set up partitions for the installation outside the installer, which is what I do.
• Start the installer. Just do it as normal, making sure you pick manual partitioning.
• Once installed, you can't just reboot. You won't be able to boot into your new system. Instead, you must start a chroot, install mdadm and lvm, as in the previous post (don't forget to modify /etc/modules too).
• Reboot into your new system. That should be everything.