grub-install fails on software RAID

[Olav Brinkmann]

Hi,

 I am trying to set up a software RAID with two partitions, one of them /boot:
 
	disk_config sda
	primary     -   256     -   -
	primary     -   2G      -   -

	disk_config sdb
	primary     -   256     -   -
	primary     -   2G      -   -

	disk_config raid fstabkey:uuid
	raid1   /boot   sda1,sdb1   ext4    rw
	raid1   /       sda2,sdb2   ext4    rw

Everything seems OK so far, but during the installation run the default GRUB_PC/10-setup script fails at

root at thehost:~# $ROOTCMD grub-install --no-floppy "(md0)"
/usr/sbin/grub-probe: Fehler: no such disk.
Auto-detection of a filesystem of /dev/md0 failed.
Try with --recheck.
If the problem persists please report this together with the output of "/usr/sbin/grub-probe --device-map="/boot/grub/device.map" --target=fs -v /boot/grub" to <bug-grub at gnu.org>

Are there any prerequisites that I'm possibly missing?

Olav