Communication association with System Interaction (Implementation)

Something that appears potentially very useful is the ability to association a Communication with a System Interaction (Implementation). 

System Interaction can be a good proxy for a deployable interface between systems / object on a system interaction diagram and that they can implement a number of different communication links on each system interaction link seems like some great synergy. Communication diagrams can focus or business fiorendly diagrams where we may want multiple links showing the various communicatin between object on the model; System Interactiosn could concentrate on the deployable system inteactions that implement the communication.

However this potential use seems to be missed. When I interpret a system interaction link I don't get anything about the communications it implements. Conversly when I interpret a ommunication link I don't get anything on the system interactions that implement it.

I've used this when from a business point of view system A communicates with system B, however in the system interaction diagram system A may have an interaction with a middleware system, via a network to get to system B. A sisngel communication may be implemented by 1 or more system interactions.  However as they are it seems any such complemantary modelling has been complete missed.

Both the System Interaction link and Communications links get the same defination options; Event (to left object), Event (to right object), Deliverable (to left object), Deliverable (to right object), and Stereotype. Not sure what the point is of having exactly the same Events and Deliverables - seems to turn system interaction into a virtual duplicate of the communication link.  Yet the assocations tab says otherwise, or at least hints at some more evloved thinking. 

Currently there seems to be little point in assocatinign communication with the system interaction if there is no simple way of getting to this information, however it looks promising.  Last time I did a Provision Entperise Architecture training course in 2011 with a partner organsiation I raised it with our instructor and he know nothing about it, nor could he see why I might find it useful, nor why the fact it would interpret would be an issue. 

Can anyone shed some light on this, or how it's supposed to be used, or even how I can get it to interpret as I'm having no luck as all.