Autofac does not currently ship out of the box with any specific message broker support. Autofac being an IoC container, not a message broker, if anything were to be added, it would be extensions supporting an external system the way Ninject's bbeventbroker works - possible assistance in wiring up event handling but not management of the actual brokering proper. (Just like Autofac doesn't do its own MVC or WCF implementations - just helpers to interface with existing systems.)
You could roll your own integration with a system like the bbvcommon Event Broker or NServiceBus using things like Autofac's lifetime events and/or custom registration sources but exactly how that would need to be done and what that would look like would depend on the system with which you're integrating. You could look at the source for other integration components to get ideas and patterns.
If you do get something working, you might consider contributing it for inclusion as an Autofac.Extras project.