Font color not displayed in notifications

According to the code, the title of the notification should display a red color font:
"<font color=red><i><b>Kernel $1 detected</b></i></font>"

However, when I try in my Ubuntu Natty installation, I see that the markup is displayed as plain text. I've looked at the desktop notifications specification and it seems that the font tag is not among the ones that should be supported:
http://www.galago-project.org/specs/notification/0.9/x161.html

I guess that the markup is working for you so I don't know if there's some package or configuration that I'm missing.