/// <summary>
        /// Find users by username and email address.
        /// </summary>
        /// <param name="authenticationToken">Encrypted forms auth token identifying the requesting user.</param>
        /// <param name="searchTerm">The value to search for.</param>
        /// <returns></returns>
        private static IEnumerable<GroupedResultOfUserDataVUqw3SxC> SearchUsers(string authenticationToken, string searchTerm)
        {
            /*
             * If you are unable to reference System.Service make sure that the project is configured to
             * use the full 4.0 framework and not the client profile.
             */
            var proxy = new UserManagementServiceClient();

            var result = proxy.SearchUsers(authenticationToken, searchTerm);

            // Handle exceptions
            if (!result.CallSuccess)
            {
                Console.WriteLine(result.FailureMessage);
                return null;
            }

            return result.ResultData;
        }