How to get SMS as send method in the Messaging&Notification module (D7)?
I've used SMS Framework for D7 ,, built a sub-module for my SMS Getway provider (it might be already there for your case),, and with my custom module controlled the rest in notifying|messaging ,,, etc


  The SMS Framework is set of modules that enables interaction between
  mobile users and Drupal using SMS. Several popular SMS gateways are
  supported and the included API allows developers to add support for
  additional gateways. The API also allows other modules to implement
  SMS features.