Admob not showing in New Windows Phone 7 Silverlig

Question

I tested my AdUnitID with Admob example and it's working fine. However, when I create a new project and write the same code as in the fundamental example (provided by google); it does not show anything? Why? Did I miss something? I tried this several times, http://code.google.com/mobile/ads/docs/wp7/fundamentals.html. It's only working with their sample project. It does not work in any other project.