resume blocked by Vista

[ulrichard]

When performing an upgrade, the WindowsInstaller decides that the computer needs a reboot after the uninstall of the old version.
The command "Reboot Computer and Resume Setup" works well but on Vista, the resume is blocked, and the user is only notified with a small message bubble in the system tray. Most users don't notice this notification. So they think that the process didn't work, and download the installer again. And now it works, except that this time, a new installation is performed instead of an update.

Is there anything that can be done so that the user doesn't miss the notification, or that the resume is not blocked by Vista?

Rgds
Richard