Hola, buenas

Estoy tratando de conectarme automáticamente a una web privada con este código:

Option Explicit
Private Declare Sub keybd_event Lib "user32" (ByVal bVk As Byte, ByVal bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long
Private Declare Function SendMessageSTRING Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String) As Long
Private Declare Function SendMessageLONG Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Const WM_SETTEXT = &HC
Private Const KEYEVENTF_KEYUP = &H2
Private Const KEYEVENTF_EXTENDEDKEY = &H1

Private Sub Form_Load()
WebBrowser1.Navigate "https://eagora.telefonica.es/portal/site/e-agora/"
End Sub

Sub Pulsar_Tecla(ByVal Tecla As Long)
Call keybd_event(Tecla, 0, 0, 0)
Call keybd_event(Tecla, 0, KEYEVENTF_KEYUP, 0)
End Sub

Private Sub WebBrowser1_ProgressChange(ByVal Progress As Long, ByVal ProgressMax As Long)
If Progress = 100 Then 'cuando carga la pagina al 100 % empieza el proceso
Dim a As Long, b As Long, c As Long, d As Long, f As Long, g As Long
a = FindWindow("#32770", vbNullString) 'la ventana padre
b = FindWindowEx(a, 0&, "syscredential", vbNullString) 'el marco oculto
c = FindWindowEx(b, 0&, "comboboxex32", vbNullString) 'el combo padre
d = FindWindowEx(c, 0&, "combobox", vbNullString) 'el combo contenedor
f = FindWindowEx(d, 0&, "edit", vbNullString) 'el textbox del usuario
g = FindWindowEx(b, 0&, "edit", vbNullString) 'el del password
Call SendMessageSTRING(g, WM_SETTEXT, 256, "password") 'pones la contraseña
Call SendMessageSTRING(f, WM_SETTEXT, 256, "usuario") 'pones el usuario
Call Pulsar_Tecla(vbKeyReturn) 'para aceptar los datos
End If
End Sub

Tengo el webbrowser creado y me deja navegar por la pagina una vez me autentifico manualmente, lo que quiero es hacer la autentificación de manera automática pero no lo consigo.

¿Me podeis echar una mano?

Gracias.