I think you need to set ServiceName property (not channelName) to your service's domain name exactly as it appears on CN property in the server certificate that you will use. P.e., if your certificate's CN=www.mydomain.com, you must set Channel.ServiceName="www.mydomain.com". Channel name my be anyone that you like. This is at client side.
At server side you need to upload your cert file to developer.windowsphone.com dashboard and to your server too (with the private key).
You can check if MPNS recognize your secure channel by checking if channel URI generated starts with https:// instead http://. This not ensure that your server can send trusted notifications since it depends on if you have the same certificate in your server and specify it correctly in all petitions, but tells you that client side is ok.
You have detailed information about how to configure your server here: http://msdn.microsoft.com/en-US/library/windowsphone/develop/ff941099%28v=vs.105%29.aspx
Best practices to implement a push notification system (including authenticated servers): http://blogs.windows.com/windows_phone/b/wpdev/archive/2013/10/22/recommended-practices-for-using-microsoft-push-notification-service-mpns.aspx