[Help-gnu-radius] How do i set an expiration date on a users password

[Julio César Mejia Vergara]

Hello,

How can i set an expiration date on a specific users password or a 
global expiration for all the users passwords?
Is it in the users file or in another file?
I'm using local password authentication via the users files.
Entry from my users file:

remoto Password = "temp", Framed-Protocol = PPP
      Service-Type = Framed-User,
      Framed-Protocol = PPP,
      Framed-IP-Address = 255.255.255.254,
      Franed-IPX-Network = 255.255.255.254,
      Framed-Routing = Broadcast-Listen,
      Framed-MTU = 1500

Thanks
Julio