Faking Collections with Typemock

Hi,

I'm trying to fake method that returns collection in Isolator for example: Hashtable
but what the fake method returned is Null while i'm expecting an Empty Hashtable.

I would expect the next test to pass:

    public class HashClass
    {
        public Hashtable Foo()
        {
            return null;
        }
    }
        [TestMethod]
        public void FakeCollections()
        {            
            var fake = Isolate.Fake.Instance<HashClass>();
            Hashtable hashtable = fake.Foo();
            Assert.IsNotNull(hashtable);
        }

- James