We model and analyse a business case from a dual view of process and service perspectives. We discover that a common understanding of transactional reliability is missing between the parties collaborating in this case. Therefore, we propose to enclose a transactional quality of service (TxQoS) specification in a service level agreement (SLA) to infuse transactional semantics into e-contracts for contract-driven service-oriented processes. A contract structure with a business terminology is designed to enable unambiguous interpretation and understanding of transactional qualities between the business and technical communities as well as between the contracting parties. A framework is developed consisting of an architecture, a mapping-matching model and a monitoring mechanism to support the TxQoS approach.