gdm battery icon not right

I have replaced lightDM by GDM as my loggin manager. The battery indicator in GDM works as expected but the icon displayed (small horizontal-shaped battery with plain charge display) is not consistant with the "power button" icon next to it and with the actual battery icon displayed in Gnome-Shell (vertical battery with dotted-like charge display ).

I expected to get the same battery indicator for both GDM and Gnome-Shell, which would look definitely better.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gdm 3.0.4-0ubuntu15
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic 3.2.9
Uname: Linux 3.2.0-18-generic x86_64
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
Date: Sat Mar 10 10:38:06 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: gdm
UpgradeStatus: No upgrade log present (probably fresh install)