Sacha,
In your scenario - the SMEs only have issues receiving ebXML msgs - not
sending.
Also - now with the new staged delivery "pull" mode - remote clients
could defer delivery until they announce their presence and "pull" queued messages waiting for them.
Seems to me that the v3.0 features actually significantly reduce the
need for SMTP at all here.
In fact we could probably create a pMode for this and template of
CPA + "pull" message sample - so the v3.0 server would place messages in a queue and then await a request to deliver them.
Now if an SME is sending a message to another SME - then those should be
routed thru an intermediary ebMS that guarantees service availability to act as the delivery server.
DW
"The way to be is to do" - Confucius (551-472 B.C.)