Mocking Public Property from Abstract Class

Using the community verison of TypeMock and attempting to mock the following:

public interface IFileUpload
{
   string SaveChanges();
}

public abstract class MyControl : System.Web.UI.UserControl
{
   public new MyPage Page { get (return (MyPage)base.Page; }
}

public abstract class MyPage : Page 
{
   public static MyPage Current
   {
      get {return HttpContext.Current.Handler as MyPage;}
   }
   public bool Validate(bool badCondition, string errorMessage)
   {
      //do validation test
      return true;
   }
}

public partial class FileUpload : MyControl, IFileUpload
{
    public string SaveChanges()
    {
   this.Page.Validate(..., ...);
   return "";
    }
}

[TestFixture]
[ClearMocks]
class UserControlInterfacesTest
{
   [Test]
   [VerifyMocks]
   public void FileUploadTest()
   {
      IFileUpload fileUpload = new FileUpload();
      Assert.IsTrue(fileUpload.SaveChanges() == "");
   }
}

I hope that all makes sense as I'm a beginner and I've stripped out some unnecessary code.

The issue I'm having is mocking the "Page" property which is actually a property of the abstract class "MyPage" and returns a casted instance of the System.Web.UI.Page property in the System.Web.UI.Control class.

I can mock "Validate" fine because it belongs to the abstract OurPage class.