Grub in RHEL6 with RAID1?

[David C. Miller]

Today I installed RHEL6 on system where I setup a RAID1 for the / partition. There is no separate /boot. When it came to the screen that asked where the grub boot loader would be installed it selected /dev/sda. Obviously I want the boot loader installed on both drives in case sda fails the system will still boot. Under RHEL5 I would pick /dev/md0 and it would install a MBR on both drives. However, I tried that now and the system won't boot. So I booted the rescue disk and attempted to install grub manually. I have done this probably a dozen times in the past with no issues at all. I simply run grub. I typed in "root (hd0,0)" and hit return but this time it says filesystem type unknown. It is the default ext4 RHEL put on the Linux auto RAID partition. How do I properly load grub to the master boot record on both of these drives? How do you manually install grub to drive that has ext4 on it?

Thanks.
David.