Using UploadValues to log into a VBB Board

[Arsenic0]

I need some help using UploadValues in order to log into a VBB Board(such as this forum).

Here is the source for the page

</td>



<td class="alt2" nowrap="nowrap" style="padding:0px">

<!-- login form -->
<form action="login.php" method="post" onsubmit="md5hash(vb_login_password,vb_login_md5password,vb_login_md5password_utf)">
<script type="text/javascript" src="clientscript/vbulletin_md5.js"></script>
<table cellpadding="0" cellspacing="2" border="0">
<tr>
<td class="smallfont">User Name</td>
<td><input type="text" class="button" name="vb_login_username" id="navbar_username" size="10" accesskey="u" tabindex="1" value="User Name" onfocus="if (this.value == 'User Name') this.value = '';" /></td>
<td class="smallfont" colspan="2" nowrap="nowrap"><label for="cb_cookieuser_navbar"><input type="checkbox" name="cookieuser" value="1" tabindex="3" id="cb_cookieuser_navbar" accesskey="c" checked="checked" />Remember Me?</label></td>
</tr>
<tr>
<td class="smallfont">Password</td>
<td><input type="password" class="button" name="vb_login_password" size="10" accesskey="p" tabindex="2" /></td>
<td><input type="submit" class="button" value="Log in" tabindex="4" title="Enter your username and password in the boxes provided to login, or click the 'register' button to create a profile for yourself." accesskey="s" /></td>
</tr>
</table>
<input type="hidden" name="s" value="" />
<input type="hidden" name="do" value="login" />
<input type="hidden" name="forceredirect" value="1" />
<input type="hidden" name="vb_login_md5password" />
<input type="hidden" name="vb_login_md5password_utf" />
</form>
<!-- / login form -->

</td>



And here is the code that i am using..the problem is what i get returned is the login page.

Dim bt() As Byte 'the returned bytes
Dim fields As New Specialized.NameValueCollection
fields.Add("vb_login_username", "UserNameHere") 'search option
fields.Add("vb_login_password", "PasswordHere") 'search box
fields.Add("Log In", "") 'button pressed
bt = wc.UploadValues(strUrl, fields) 'send fields and retrieve response
Dim strhtml = System.Text.Encoding.ASCII.GetString(bt) 'convert to text