[gdm-list] Login theme customization : background color for entry field

[Huy Phan <dachuy gmail com>]

Hi everybody, 
I'm using Ubuntu 9.04 and trying to customize my login theme, I've dug around gnome.org and gnome-look, but hadn't found anyway to change the color of the entry field, seems that it's always white. 
I believe this is not a new issue and there're should be someone solved it already, but I don't see any solution on google though. 
Do you have any idea ?