to use wmi in your c# files you have to use the System.Management namespace
and query voor the iis wmi-classes:

ManagementObjectSearcher Searcher = new ManagementObjectSearcher();
  ManagementScope Scope = new ManagementScope("root\\iis name have to look
for it");

  Searcher.Scope = Scope;
  SelectQuery Query = new SelectQuery();

  StringBuilder queryString = new StringBuilder();
  queryString.Append("SELECT * FROM bla bla");
etc
etc
etc

to find all the parameters and methods you can use cim-studio

greets clemens