Business processes constitute an integral part of today's IT applications. They contain transactions as essential building blocks to ensure integrity and all-or-nothing behavior. The Business Process Execution Language is the dominant standard for modeling and execution of business processes in a Web service environment. BPEL itself contains a transaction model based on compensation, that describes the (local) transactions in a business process. The WS-Coordination framework deals with (external) transactions between Web services and is used to define the transaction behavior between a BPEL process and its partners. In this paper, we investigate how external transactions between Web services interrelate with local transactions of BPEL.