Changing the WhenCalled behaviour

Hallo,

I want to change the WhenCalled behaviour after some time during my test. Unfortunately typemock (7.4.0.0) everytime uses the first assignment.
Ihave the following testcase:
- My method does some data manipulation, but only if called first time.
- the manipulated data is in space and will be send to a web service.
- If the web service is not availible or throws an exception I have to call it again but without the data manipulation.
- I want to verify that the correct manipulated data is send to the webservice.

For this I made this test:
[Test]
public void CloseCaseExecute_FirstTimeExceptionSecondTImeOk_ValueEpanded()
{
Data data = null;
SetValidator();
Isolate.WhenCalled(() => webservice.AnyCall(null, false)).WillThrow(new Exception(""));
viewModel.Lastname = "abc";

// The last name is epanded by AP.
CloseCaseAndWait();

Isolate.WhenCalled(() => webservice.AnyCall(null, false)).DoInstead(x => data = ((Data)x.Parameters[0]));

//Verification if its still "AP last name" and not e.g. "AP AP lastnáme".
//But the web service call throws still an exception.
CloseCaseAndWait();

Assert.AreEqual("AP abc", viewModel.Lastname);
}

thanks for any reply and I would be happy to find a solution.