Business Process Execution Language for Web Services (BPEL) is becoming the industrial standard for modeling web service based business processes. The check of behavioral compatibility for web service composition is one of the most important topics. The commonly used reachability exploration method focuses on verifying deadlock-freeness. When this property is violated, the states and traces in the reachability graph only give clues to re-design the composition. The process must then repeat itself until no deadlock is found. In this paper, multiple web services interaction is modeled with a Petri net called Composition net (C-net for short). The problem of behavioral compatibility among web services is hence transformed into the deadlock structure problem of a C-net. If there exist incompatibility cases, a policy based on appending additional information channels is proposed. It is proved that the policy can offer a good solution as well as be mapped back into the original BPEL models automatically.