A nice trick that used to work (and may still work) was to log into Sprint's online account management, then go to the area where you can change passwords and set permissions for use of Vision and purchases. (settings and passcodes is the name of the menu if you are on the Ensemble billing system).

Change your vision user name or password, and it should automatically send the updates to your device (re-provision).

The standard "may take up to 4 hours" thing is in effect, but usually it happens right away.