[CentOS] Boot from FC SAN CentOS 5.1 x86-64

Anything special needed to boot from a SAN in
CentOS 5.1 x86-64 ?

We have a new system running a QLA2342 FC HBA connected to
a SAN, have a volume exported to it and would like to boot
from it.

We PXEboot kickstart and that works, the installer sees
the disk, installs to it, and reboots. When GRUB tries to
load all it prints is "GRUB" and sits there.

When we try the Xen edition of CentOS 5.1, when GRUB tries
to load the screen goes black and the system reboots.

When we try VMWare ESX 3.5.0 it works perfectly, so the
BIOS configurations and the SAN config is good, something
specific with CentOS 5.1.

I see in the release notes that SAN boot is supported, but
doesn't give any special instructions.

Anyone else booting CentOS directly from a FC SAN ? Any
special considerations needed for multipathing and
stuff when booting ?

thanks

nate