//Create a class that implements IUserType:

[Serializable]
    [DataContract(IsReference = true)]
    public class ProvisioningUserType : Entity, IUserType {
        [DataMember]
        public string Alias { get; set; }

        [DataMember]
        public string Name { get; set; }

        [DataMember]
        public IEnumerable<string> Permissions { get; set; }
    }

    //Create a user with the following code:

 var userService = ApplicationContext.Current.Services.UserService;

    var email = "youremailhere";
    var date = DateTime.Now;
    var userType = new ProvisioningUserType()
    {
        Alias = "admin",
        Name = "Administrators",
        CreateDate = date,
    };
    var user = userService.GetByEmail(email);
    userService.SaveUserType(userType);
    if (user == null) {
        // Create a new user
        var newUser = userService.CreateUserWithIdentity(email, email, userType);
        newUser.RawPasswordValue = (Membership.Providers["UsersMembershipProvider"] as UsersMembershipProvider).HashPasswordForStorage("password"); ;
        // Save the new user
        userService.Save(newUser);
    }