Actor-based webservice - How to do it properly?

In the past few months, me and my colleagues have successfully built a server-side system for dispatching push notifications to iPhone devices. Basically, a user registers for these notifications via a RESTful webservice (Spray-Server, recently updated to use Spray-can as the HTTP layer), and the logic schedules one or multiple messages for dispatch in the future, using Akka's scheduler.

This system, as we built it, simply works: it can handle hundreds, maybe even thousands of HTTP requests a second, and can send out notifications at a rate of 23,000 per second - possibly even more if we reduce log output, add multiple notification sender actors (and thus more connections with Apple), and there might be some optimization to be done in the Java library we use (java-apns).

This question is about how to do it Right(tm). My colleague, much more knowledgeable about Scala and actor-based systems in general, noted how the application isn't a 'pure' actor-based system - and he's right. What I'm wondering now is how to do it Right.

At the moment, we have a single Spray HttpService actor, not subclassed, that is initialized with a set of directives that outlines our HTTP service logic. Currently, very much simplified, we have directives like this:

post {
  content(as[SomeBusinessObject]) { businessObject => request =>
    // store the business object in a MongoDB back-end and wait for the ID to be
    // returned; we want to send this back to the user.
    val businessObjectId = persister !! new PersistSchedule(businessObject)
    request.complete("/businessObject/%s".format(businessObjectId))
  }
}

Now, if I get this right, 'waiting for a response' from an actor is a no-no in actor-base