I have to say that I am also pretty excited about this project.
In relation to occasionaly connected clients, because ISB crosses over the internet it is a good point to raise the question of occasionaly connected clients and services.
WS-Discovery could apply quite nicely. Standardized Bye/Hello and Probe/Resolve messages could offer a WS* compliant solution to provide presence awareness and discovery and as well a s ensuring interoperability.
Are there plans to integrate WS-Disco in a later release?