Web services have been emerging as a promising technology for business process integrations. Due to their long-duration and loosely coupled properties, Web service based applications require transactional support beyond traditional transactions. Some web service standards have been proposed to deal with the transaction aspect of Web service applications. Compensation is a commonly used mechanism in these standards for backward recovery. However, the compensation mechanism usually adopted is too fixed and cannot satisfy the various requirements of different applications. In this paper, we first analyse the compensation protocol of current standards. Then we enrich the protocol by allowing flexible compensation and extend our proposed multiple-compensation mechanism in web service environment. The implementation of the extended compensation mechanism is discussed and the incorporation of the mechanism into current standards is also addressed.