subclass corresponding to xsd extension decoded incorrectly as parent class from wcf webservice response

Steps to reproduce:
1. Install the WCF webservice sample on an IIS server by creating a virtual diretory. Dotnet 3.5 should be installed prior.
2. Setup the flexunit test project by the name of AdbWCFTest.7z.
3. Go to line number 18 in WCFTestSuite.as and change the endpoint to your webservice sample.
4. Run the main application.

Actual Results:
two test cases pass and one fails.
The problem is that the webmethod signature specifies the parent class while the server returns the subclass defined by the extension keyword in xsd schema. When an array of such items is sent(TestGetData3),it is decoded correctly but when a single item is sent(TestGetData2), it is decoded as the parent class only. The child class properties can never be accessed and are lost.

Expected Results:
all testcases should pass.

Workaround (if any):
none.