ClearMocks not working well with Inherited Test Class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MbUnit.Framework;
using TypeMock.ArrangeActAssert;
using TypeMock;

namespace MBUnitProblem
{
    [TestFixture, ClearMocks]
    public class BaseFixture
    {
        protected int count;
        [FixtureSetUp]
        public void FixtureSetUp()
        {
          
        }

        [SetUp]
        public virtual void SetUp()
        {
            

        }

        [TearDown]
        public void Clean()
        {
            count = 0;
        }



    }

    public class DerivedFixture : BaseFixture
    {

        public override void SetUp()
        {
            base.SetUp();
            count++;
            Assert.AreEqual<int>(1, count);
        }

        [Test, Isolated]
        public void test1()
        {
        }

        [Test, Isolated]
        public void test2()
        {
        }
    }
}

TestCase 'MbUnit v3.0.6.763/MBUnitProblem/DerivedFixture/test1' failed: 
   Expected values to be equal.
   
   Expected Value : 1
   Actual Value   : 2
   
   C:Documents and Settings	estMy DocumentsMahaLongMBUnitProblemMBUnitProblemClass1.cs(45,0): at MBUnitProblem.DerivedFixture.SetUp()

TestCase 'MbUnit v3.0.6.763/MBUnitProblem/DerivedFixture/test2' failed: 
   Expected values to be equal.
   
   Expected Value : 1
   Actual Value   : 2
   
   C:Documents and Settings	estMy DocumentsMahaLongMBUnitProblemMBUnitProblemClass1.cs(45,0): at MBUnitProblem.DerivedFixture.SetUp()

Disposing the test runner.