Assign a Static IP Address to User

Is there a way to assign a static IP address to users form command line in Windows Server?

I mean, in Windows Server 2003, VPN server, how to set a value from command-line to a "Assign a Static IP Address" in "Dial-In" tab in User properties.

Every time I re-install VPN server, I have to assign IP addresses to users manually. I can create a user, permit dial-in permission from command line, but can't assign IP address

Pls, help.