Sessions variables getting lost

[vixez]

Hey,
I've spend ages looking into the problem, but I cant find it.

This is my page code

 Protected Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click
            Dim blnLogin As Boolean
        blnLogin = Login(txtUserLogin.Text, txtPassword.Text)

            If blnLogin = True Then
            Session("LoggedIn") = ""
            Session("LoggedInUser") = txtUserLogin.Text
            Session("LoggedInID") = GetUserID(txtUserLogin.Text)
                lblNotice.Text = "Login succeeded: " '& GetFriends(Session("LoggedInUser"))
            Else
                lblNotice.Text = "User not found"
        End If
    End Sub

    Protected Sub btnAddToWall_Click(sender As Object, e As EventArgs) Handles btnAddToWall.Click
        MsgBox(Session("LoggedInID"))
    End Sub

So after the user presses the Login button there should be 3 variables stored in a session, this works (checked using trace='true')

Session State
Session Key Type Value
LoggedIn System.String
LoggedInUser System.String User
LoggedInID System.Int32 2

That's fine. Now I click on the AddToWall button to check if I can get the LoggedInID, it shows an empty messagebox.

In the trace there are no Sessions keys left.
How can I make it keep the keys after postback/after clicking on buttons?

Note: When calling GetFriends(Session("LoggedInUser")) in the same sub as the Login button the variable does get passed to the class with sub GetFriends()

Here's my web.config

<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
    <sessionState timeout="30" />
  </system.web>

</configuration>