Grub displays WindowsXP boot partition as "Vista"

Binary package hint: grub

Ubuntu 11.04 has dual boot which I installed on a Lenovo T-61P. sda1 is NTFS format containing Windows XP. The end of the drive has another NTFS partition containing an IBM XP Recovery System for Windows XP. The laptop previously had a Vista system on it as evidenced by a worn Vista COA label on the underside. There is also a new IBM COA label for XP. I was told by the seller that the IBM Refurbisher wiped out the Vista install and reformatted with XP.
On boot, Grub displays Vista as the other operating system instead of XP. XP boots and works fine as does Natty
I think there is a bug in /etc/grub.b/os-prober which misidentifies the version of Windows.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: grub (not installed)
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Mon May 23 16:31:18 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: grub
UpgradeStatus: No upgrade log present (probably fresh install)