AFAIK, you can’t manage the multi-domain feature of Webtop5 on NS7.
That feature is provided for support on different setups, such as our XStream based cloud services.
The Webtop local domain, will allow you to manage different Webtop5 domains with authentication managed directly by Webtop inside its database (infact you can add and setup users directly in Webtop, and users can change their password directly inside Webtop).
In this case, all services will function, but you will need to setup mail accounts externally and provide account details directly on each user settings.
You may add new Webtop ldap domains if you have access to different ldaps that manage different domain accounts, but again, I don’t know if you can do this with NS7 on a single machine.
Gabriele