How Do I Get GRUB to See the External USB Drive?

[Scarletdown <scarletdown@gmail.com>]

I just purchased an external USB drive in hopes that I could toss an XP
build on it real quick without messing with everything on the internal
drives (friends wanting me to try Lord of the Rings Online which doesn't
work with Cedega is one of the reasons...)

Anyway, I got what I think is a working XP install on the drive.
However, GRUB does not recognize that the drive is there until after I
am fully booted into Linux.

When I go to a GRUB command prompt by hitting c when the menu comes up,
I enter the command root (hd TAB.

This shows available drives as hd0 (the EIDE drive that the system boots
from), hd1 (a 9GB internal SCSI drive), and hd2 (a 500GB internal SATA
drive).

When I get fully booted up and fire up konsole, I enter the grub command
and again do root (hd TAB.

This time I get hd0, hd1, hd2, hd3

And further, root (hd1, TAB shows:

 Possible partitions are:
   Partition num: 0,  Filesystem type is ext2fs, partition type 0x83
   Partition num: 1,  Filesystem type unknown, partition type 0x7
   Partition num: 2,  Filesystem type unknown, partition type 0x7

(That second one is where the XP install is at)

So it's obvious that GRUB can see external USB drives.  However, it is
not visible to GRUB there at boot time.  Is there any way to force GRUB
to actually see external drives?