I saw this posting from Steve Jones - Why BPM screws up SOA and I must say that I recognize the statements being made. Especially the next one:
If you are doing BPM and then just saying "step = service" then you are doing VISUAL Cobol and replacing function calls with service. The fact that you are using WS-* or XML does not make these elements services. As the SOA-RM says "A service is a mechanism to enable access to one or more capabilities", so it is possible for it to be a single capability, but that is certainly not the only, or indeed the most likely, number of capabilities in a service.