RAID Lv 1: Grub fails to install!

[oxy]

Hi all,

the motherboard ASUS P8Z68-V LE offers a RAID option. I setup
RAID1 there (2 discs) and installed Ubu 11.10. Went fine till the end,
when Grub failed to install (it was trying on a /dev/sda device, non-existent
because it was inside the RAID). The installer asks for an alternative
installation
point and i tell the RAID device that was given as one of the options.
Installation continues (default partitioning) till the end, I boot the
system and  ... black screen!

Any help? Thanx in advance!
oxy

PS: they are 2 identical SATA discs. The motherboard supports the
"Intel rapid storage technology - option ROM" (??)