try *228 option 5 i think
edit: eh.. I know you already tried this, but this is the code for updating your prl...
i had to call into metro support earlier this weak cuz I couldn't get the option to work, and the lady told me this is the correct manner in which to do it. But I could not get that option. She told me if I couldn't get it to work that i woud have to call back from another phone so they can try to do it remotely.
last edit: you could always obtain the latest prl and do it manually.