Creating a Permanent Lease

I am in a unique position where I am deploying Nocat in rental housing where
they want only first time users to create a new account and then
authenticate. The rest of the time they are given free internet with no
splash and no authentication. The users can also add up to 3 mac addresses
per account which also don't need splash/authentication.

New users need to authenticate against a Java Struts Application that is at
a data center - this is part of their business process to identify that the
users are valid tenants.

I'm trying to use Nocat and since I'm not much of a perl expert I am hoping
to get some advice from the developers on this list as to how to approach
this scenario.

Thanks in advance,
Vijesh Mehta