Issue - R45 - BPEL partner link assignments (revisit issue R13)

1. Receive PartnerLinkA, Operation1, messageExchange=First
2. Receive PartnerLinkA, Operation1, messageExchange=Second


     ... some work (a) ...


3. Reply PartnerLinkA, Operation1, messageExchange=First
4. Reply PartnerLinkA, Operation1, messageExchange=Second


     ... some work (b) ...