Messages represent an abstract definition of the data being transmitted. A message consists of logical parts, each of which is associated with a definition within some type system. WSDL messages are top level objects that can be referenced by an operation's input, output and fault elements (within a port type).
You can create a message using the Outline view by right-clicking the Messages folder and clicking Add Message.
To create a new message for your input, output, or fault element, complete the following steps:
Note: Messages are referenced within a port type (specifically by an operation's input, output and fault objects). The input, output and fault objects within a binding do not reference messages. Hence you cannot create a new message by right clicking on a input, output, or fault within a binding (these are also known as binding input, binding output and binding faults).