Unable to return Output parameters from Stored Proc in Dot Net ---specified cast is not valid ---

I had noticed this topic being posted before but no real solution. What I and others are trying to do is...
from an ASPX page call upon a component's function that hits a database using a stored procedure, and return the output parameter.

My specifics are adding a new user to a DB, then return the @@Identity for the use of the next page after the user is added. The stored proc works, I can run from a VB6, Query Analyzer, or ASP page and get the expected results. So the problem is something I and others are doing in Dot Net. I receive the error "specified cast is not valid " when attempting to do execute the procedure and return the output parameter. I've tried using different data types, but doesn't change the results.

Code for NewUser Function...

Imports System.Data

Imports System.Data.SqlClient

 

 

Public Class cLogin

    Inherits cConnection       'Connection Object
 

   
Public Function NewRefPortalUser(ByVal UserName As String, ByVal Password As String, ByVal FirstName As String, ByVal LastName As String) As VariantType

 

        Dim objCrypto As EncryptIt      'Declare Encryption object

 

        Dim varID As VariantType        'Declare variable for ID of new record

 

        objCrypto = New EncryptIt()     'Instantiate Encryption object

 

        Password = objCrypto.EncryptString(Password)    'Encrypt the password in DB

 

        objCrypto = Nothing             'Destroy Encryption object

 

        Dim MyCommand As SqlCommand = New SqlCommand("usp_NewRefPortalUser_INS")

 

        MyCommand.CommandType = CommandType.StoredProcedure

 

        Dim workParam As SqlParameter = Nothing

 

        MyCommand.Parameters.Add(New SqlParameter("@FirstName", SqlDbType.VarChar, 30))

        MyCommand.Parameters("@FirstName").Value = FirstName

 

        MyCommand.Parameters.Add(New SqlParameter("@LastName", SqlDbType.VarChar, 30))

        MyCommand.Parameters("@LastName").Value = LastName

 

        MyCommand.Parameters.Add(New SqlParameter("@UserName", SqlDbType.VarChar, 50))

        MyCommand.Parameters("@UserName").Value = UserName

 

        MyCommand.Parameters.Add(New SqlParameter("@Password", SqlDbType.VarChar, 50))

        MyCommand.Parameters("@Password").Value = Password


        workParam = MyCommand.Parameters.Add(New SqlParameter("@Identity", SqlDbType.Variant, 4))

        workParam.Direction = ParameterDirection.Output


        Connect(True)                   'Connect to DB

        MyCommand.Connection = CNx

        MyCommand.ExecuteScalar()

        varID = MyCommand.Parameters("@Identity").Value

        MyCommand.Dispose()

        MyCommand = Nothing  
 
        Connect(False)

        Return varID

End Function



Here is the code from the ASPX.vb page

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim objportal As clsRefPortalLogin.cLogin

        objportal = New clsRefPortalLogin.cLogin()

        Dim varID As VariantType

        varID = objportal.NewRefPortalUser("Jeremy", "powerfull", "Jeremy", "Pettit")  

        objportal = Nothing

        Response.Write(varID)
       

    End Sub