I have written a GUI (call it MyGUI) for ClickOnce deployment on any given client site. That GUI installs and configures a Windows Service (MyService), using the method described here by @Marc Gravell. Here's my code, run from inside MyGUI, which contains a reference to MyService:

using (var inst = new AssemblyInstaller(typeof(MyService.Program).Assembly, new string[] { })) {
  IDictionary state = new Hashtable();
  inst.UseNewContext = true;
  try {
    if (uninstall) {
      inst.Uninstall(state);
    } else {
      inst.Install(state);
      inst.Commit(state);
    }
  } catch {
    try {
      inst.Rollback(state);
    } catch { }
    throw;
  }
}

Take note of that first line: I'm grabbing the assembly for MyService, and installing that. Now, trouble is, the way I've done the deployment, I'm effectively referencing the service's EXE file from the GUI's app folder. So now the service fires up and starts looking for stuff in the MyService.config file, and can't find it, because it's living in someone else's app folder, with only the GUI's MyGUI.config file present.

So, how do I get MyService.config to be available to the service?