A major drawback of using SOAP for application integration is its enormous demand for network bandwidth. Compared to classical approaches like Java-RMI and Corba, SOAP messages typically cause more than three times more network traffic. In this paper we will explore compression strategies and give a detailed survey and evaluation of state-of-the-art binary encoding techniques for SOAP. We also introduce a new experimental concept for SOAP compression based on differential encoding, which makes use of the commonly available WSDL description of a SOAP Web service. We do not only conduct a detailed evaluation of compression effectiveness but also provide the results of execution time measurements.