User Account Configuration

[Patrick Meyer]

Greetings!
I am using Freeradius2 2.2.0 on a pfsense 2.1 RC1 firewall to support authentication for a captive portal.
I see that it is possible to expire a user account in Freeradius. I am wondering if I can specify a date and time to make the account effective. For instance, I know I have a user starting in 30 days. Can I configure the account today to enable the user in 30 days?

Regards,

Patrick