Violates "Notifications Specification" by using <span> tags

The "Desktop Notification Specification" (http://www.galago-project.org/specs/notification/0.9/x161.html) allows only a very limited set of markup. mail-notification emits '<span weight="bold">' tags (which can be expressed by the supported <b> ones) which makes the generated messages difficultly to read in some notification daemon implementions.

I will attach a screenshot showing a message generated by xfce4-notifyd.

mail-notification-5.4-36.fc15.x86_64 (Fedora 15)
xfce4-notifyd-0.2.1-2.fc15.x86_64