The service oriented architecture (SOA) reference architecture is intentionally simplistic at a high level but it holds some surprises when you look closely at how components really interact. This is especially true in relation to the placement of business process management (BPM) componentry. We discuss the most common design questions including: Is BPM a consumer or provider of services? To what extent should a user interface, be decoupled from the BPM runtime? How do we retain agility in BPM while adhering to the architectural separation of SOA? These subtleties are critical when designing solutions to reap benefits of both SOA and BPM simultaneously.