Types describe all the data types used between the client and server. WSDL is not tied exclusively to a specific typing system, but it uses the W3C XML Schema specification as its default choice.
WSDL allows type systems to be added via extensibility elements. An extensibility element may appear under the types element to identify the type definition system being used and to provide an XML container element for the type definitions.
To add an XSD type or element to your WSDL file, in the design workspace, click the arrow icon to the right of the port type object.
The XML schema editor opens.
For more information about XML schemas, see the site http://help.eclipse.org/indigo/topic/org.eclipse.wst.xsdeditor.doc.user/topics/cxmlsced.html.