Flex不支持SOAP1.2

       Flex 3只支持SOAP1.1，不支持SOAP1.2：document

       Flex applications can interact with web services that define their interfaces in a Web Services Description Language 1.1 (WSDL 1.1) document, which is available as a URL. WSDL is a standard format for describing the messages that a web service understands, the format of its responses to those messages, the protocols that the web service supports, and where to send messages. The Flex web service API generally supports Simple Object Access Protocol (SOAP) 1.1, XML Schema 1.0 (versions 1999, 2000, and 2001), and WSDL 1.1 RPC-encoded, RPC-literal, and document-literal (bare and wrapped style parameters). The two most common types of web services use remote procedure call (RPC) encoded or document-literal SOAP bindings; the terms encoded and literal indicate the type of WSDL-to-SOAP mapping that a service uses.

       Flex 4也不支持，详见Adode Forums。

       所以在Flex和WCF的通信只能使用时，WCF只能使用SOAP.1，basicHttpBinding默认使用SOAP1.1。