remoting - ClientSponsor class

[nfung]

QUESTION 1: Does anyone know how to work with this class? I need some code snippet on how to work with ClientSponsor.

QUESTION 2:
I also tried this on server side (console app hosting the remote object):

using System.Runtime.Remoting.LifetimeServices;

LifetimeServices.LeaseTime = TimeSpan.FromMinutes(3);
LifetimeServices.RenewOnCallTime = TimeSpan.FromMinutes(3);

But an RemotingException was thrown on server side, complaining that "LeaseTime can only be set once within an app domain".

QUESTION 3: extracted from MSDN:
context: <lifetime> element in config file.
Quote: "Contains information about the lifetime of all client-activated objects serviced by this application."

I thought "lifetime" applies to:
a. server-activated Singleton
b. client-activated

But according to MSDN, it seems that it only applies to "client activated" remote objects.

QUESTION 4: Can I modify config files at runtime? Do I need to restart server for modifications on config files to take effect?

Thanks!