Message instance files provide a method for simulating the message data received back from web service partners. You can manually enter the received message data into this XML file or load a file through the test mode of the SOA Composite Editor. For example, the following message file simulates a credit rating result of 900 returned from a partner:

<rating xmlns="http://services.otn.com">900</rating>

For more information about loading message files into test mode, see Editing the Contents of Test Cases in Test Mode in the SOA Composite Editor.