We want to give access to some Windows Server users so they can remotely have access to our server and download from a special folder of the server.

The licenses we give to users, are time base. There should be 1 month, 2 month, ..., 1 year, ... licenses.

CURRENT SITUATION (WHAT I DON'T WANT):

When users are created and added to the OS, a solid expiration date is given.

WHAT I WANT:

Users' expiration date should be calculated automatically after first login. The user might not need his account right when purchases the license.

In another words:

When a license of the user we create is purchased at Jan 1st, he should use the license until Feb 1st. No matter whether he really logs in or not. He cannot come Feb 5th and begin using his license because that has expired then.

What I want is that when he comes at Feb 5th and begins using, the license update until March 5th.

CLARIFICATION (Update after MDMarra's comment)

• Working environment is Windows Server 2012.

• By the word 'user', I mean Native Windows Server Users. Whenever a new person purchases a license with me, I create them manually using net user command like this:

  net user ali pass /add /expires:2013-12-25