Are you installing from a local CD, or via Virtual Media over the iLO?
I am installing from a local CD.
Try removing everything from your %post and make /boot it's own NATIVE partition, not LVM
/boot is primary partition and not a part of LVM (check the ks file
posted with the original post). Also I added those %post commands
later, it was not working anyway so I thought I will try installing
Grub through %post.
Installation always went smooth but when I try to boot from the hard
disk, nothing is coming up. So it looks like a problem with grub
getting installed on the MBR.
Cheers.