amd64-current and grub?

[Carl Brewer <carl%bl.echidna.id.au@localhost>]

Hello,
I'm trying to set up a xen 3 HVM server with 6GB of RAM, and to do this 
need either i386-current or amd64-current, so I figured I'd try amd64.

So far I'm stuck on getting the box to boot with grub.  Here's what I did :

Grabbed an iso of amd64 from HEAD (20080304 from memory), installed it 
on an Intel Core2Duo 8200 cpu machine.  Set up the partitions with / as 
400mb (smaller than 512mb as recommended in the xen howto)

Installed emulators/netbsd32_compat40
Installed sysutils/grub from a package pulled from ftp.netbsd.org 
(grub-0.97nb8.tgz) using pkg_add -f <>
Ran grub-install, it seemed happy.

Then the machine rebooted (power outage ... and the test box is not on 
the UPS!).  It started up grub 1.5, but each time I try and tell it 
where the kernel is it gives me an
error 13: invalid or unsupported executable format

from
grub> kernel /netbsd

I also tried
grub> kernel --type=netbsd /netbsd
Same error ...

I got the same error with the DOM0 kernel, but oddly if I installed the 
xen kernel compiled from pkgsrc (syutils/xenkernel3) and told grub about 
it :

grub> kernel /xen.gz

it would then boot the xen kernel! I hadn't set up xen to know where to 
find /netbsd, but that I think I can handle, once I can get a basic grub 
system running anyway.

I've tried a couple of reinstalls and keep getting the same response 
from grub - I haven't set up menu.1st, is that the problem?  And is 
there a dummies guide to grub and amd64? (or for that matter, grub and 
i386-current?).

Can anyone point me at some doco to help me get this going?  I'm quite 
keen to get this box up and being a nice xen server so I can retire a 
few old boxes and cut down on power use etc.

thanks!

Carl