In the WSDL view, right-click the Extensibility Elements node and choose Add -> Property Alias.
A property alias node appears under the Extensibility Elements node.
If the Properties window is not visible, choose Window -> Properties.
Select the property alias node.
Specify values for the propertyName and ElementOrTypeOrMessagePart properties.
These properties enable you to map data from a message into a property value.
To add a query, right-click the property alias node and choose Add -> query.
A query node appears. The query node enables you to set the query language and the text of the query.