addMessage($name, $parts) method adds new message description
to the WSDL document (/definitions/message element).
Each message correspond to methods in terms of Zend_Soap_Server
and Zend_Soap_Client functionality.
$name parameter represents message name.
$parts parameter is an array of message parts which describe
SOAP call parameters. It's an associative array: 'part name' (SOAP
call parameter name) => 'part type'.
Type mapping management is performed using addTypes(),
addTypes() and addComplexType()
methods (see below).
Note
Messages parts can use either 'element' or 'type' attribute for typing (see http://www.w3.org/TR/wsdl#_messages).
'element' attribute must refer to a corresponding element of data type definition. 'type' attribute refers to a corresponding complexType entry.
All standard XSD types have both 'element' and 'complexType' definitions (see http://schemas.xmlsoap.org/soap/encoding/).
All non-standard types, which may be added using
Zend_Soap_Wsdl::addComplexType() method, are described
using 'complexType' node of '/definitions/types/schema/' section of WSDL document.
So addMessage() method always uses 'type' attribute to
describe types.