User.IsInRole() does not work for custom Role Provider

I setup a relative simple role provider. The problem is that User.IsInRole() fails. 
I have this test code:
Debug.WriteLine(Roles.Provider.IsUserInRole(Membership.GetUser.UserName, "Portal")) Debug.WriteLine(Roles.IsUserInRole(Membership.GetUser.UserName, "Portal")) Debug.WriteLine(User.Identity.Name) Debug.WriteLine(User.Identity.IsAuthenticated) Debug.WriteLine(User.IsInRole("Portal")) OutPut from above:
Roles.Provider.IsUserInRole(Membership.GetUser.UserName, "Portal") returns True Roles.IsUserInRole(Membership.GetUser.UserName, "Portal") returns False User.Identity.Name returns kallal@msn.com User.Identity.IsAuthenticated returns True User.IsInRole("Portal") returns False <--- br ...