Problems mocking private methods

I am trying to mock a call to a private method but seem to be unable to do so.

This is an example of what I'm trying to test.

public class MyClassToTest
{

    public bool TestInternalMethod(int valueToTest)
    {
        bool result = IsNumberEven(valueToTest);
        return result;
    }

    private bool IsNumberEven(int valueToTest)
    {
        bool result = (valueToTest % 2) == 0;
        return result;
    }

}

And I've tried both of the test below.

/// <summary>
///A test for TestInternalMethod
///</summary>
[TestMethod()]
public void TestInternalMethodTest1()
{
    MyClassToTest target = new MyClassToTest();
    MyClassToTest_Accessor accessor = new MyClassToTest_Accessor();
    MockManager.Init();
    MockManager.ClearAll();
    using (RecordExpectations recorder = RecorderManager.StartRecording())
    {
        accessor.IsNumberEven(7);
        recorder.Return(true);
    }
    bool actual = target.TestInternalMethod(7);
    Assert.AreEqual(true, actual);

    MockManager.Verify();
}

/// <summary>
///A test for TestInternalMethod
///</summary>
[TestMethod()]
public void TestInternalMethodTest2()
{
    MyClassToTest target = new MyClassToTest();
    MockManager.Init();
    MockManager.ClearAll();

    Mock mockObjectTest = MockManager.Mock(typeof(MyClassToTest));
    mockObjectTest.ExpectAndReturn("IsNumberEven", true);

    bool actual = target.TestInternalMethod(7);
    Assert.AreEqual(true, actual);

    MockManager.Verify();
}

In both cases, the private method is not being mocked and the result is coming out as false even though I coded to return true for the call to IsNumberEven. Can anyone see what I'm doing wrong?

Oh, yes. I'm using VS 2008, .Net 3.5 in WIndows Vista 64 bit.

TIA

John