Problem with invoking WS, which uses complex data structure

Hi All
Im using WM IS 8.2

I got problem with consumer WSD (wsdl comes from RightNow system). In wsdl file used to create consumer WSD there is a quite complex schema. In general there is a base type (lets call it A). Then there is also B type which contains declaration like this:
<xs:complexType name=“B”>xs:complexContent<xs:extension base=“A”>
Then I have an operation “Create”, which has to be called. This operation has a request message
<wsdl:message name=“CreateRequest”>
<wsdl:part name=“parameters” element=“rnm:Create”/>
which is
<xs:element name=“Create” type=“CreateMsg”/>
<xs:complexType name=“CreateMsg”>
<xs:element name=“RNObjects” type=“A” minOccurs=“1” maxOccurs=“unbounded”/>
… some other fields

Now I have to call “create” in order to create object of type B. However, when I do this I got error:
[ISS.0088.9138] Input parameters do not conform to targetInputSignature:
errorMessage=[ISC.0082.9026] Undefined Object found
Type A has not got defined any field “Name”, because it comes from type B.

For me such construction is very similar to casting to base type from Java.

My question is: is IS is able to handle such situation ?