Changes of "lifetime" under "system.runtime.remoting" in Web.config are not being applied

Question

According to this article, the LifetimeServices properties (LeaseTime, RenewOnCallTime etc.) can be changed in the application configuration like this:

<configuration>
   <system.runtime.remoting>
      <application>
         <lifetime 
          leaseTime = "10M" 
          sponsorshipTimeOut = "1M"
          renewOnCallTime = "15M" 
          LeaseManagePollTime = "8s"
         />
      </application>
   </system.runtime.remoting>
</configuration>

In my ASP.NET web application hosted in IIS, I have extended the Web.config according to this example by adding a "system.runtime.remoting" section inside the "configuration" section. However, for some reason my values are never applied and the default values (e.g. five minutes for the LeaseTime property) are used. I also tried to create a new "app.config" file in the same directory but this also did not work. What am I doing wrong and how can I force my application to use the values from the configuration instead of the default values?