Display admob banner with google-play-services...

I am trying to display admob banner using google-play-services_lib. It doesn't work and I have no clue. To implement admob using AdMobUnityPlugin.unitypackage, it requires to add GoogleAdMobAdsSdk.jar into Assets/Plugins/Android. But google-play-services_lib already has GoogleAdMobAdsSdk, I believe. So i didn't add the file. And admob banner doesn't appear. Looks like admob banner is not called. If I add the GoogleAdMobAdsSdk, compile error pops up.

What more should I do for it? I've been spending lots of time. Thanks in advance for any help.