1. How does the above can be achieved using JMS protocol?Where would you like to pitch-in JMS? You want to receive inbound message at B2B over JMS or between SOA and B2B, you want to use JMS?
2. Will SOA Composite having B2B Adapter receive operation has first operation can get triggered automatically or not as soon as EDI----->XML message is found?Yes, it can be triggered. Provided the steps in your another thread.
3. will B2B Adapter receive operation in SOA Composite will take EDI--------> xml msg as opaque?No, if while modelling B2B adapter, you selected a doc-def otherwise yes.