SharePoint 2010 FBA with UAG SSO

We are working on Extranet site which is on UAG. We followed below blog to configure single sign on in SharePoint

http://microsoft-iag.blogspot.com/2010/10/uagenable-sso-by-passing-user.html

User able to see SharePoint FBA site when login through UAG (outside network) with forms authentication.

Here we have a problem like it is showing windows/forms authentication screen (as shown in below picture)

When users selects “forms authentication” from dropdown it is going to home page without asking credentials. however it should not ask.

for this I have implemented java script code (in the sign in page)to redirect to home page automatically with out selecting dropdown.

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\IDENTITYMODEL\LOGIN

<asp:Content ContentPlaceHolderId="PlaceHolderMain" runat="server">

<script language="javascript" type="text/javascript">

    function changeDropdownValues() {

        var ddlLogin = document.getElementById("<%=ClaimsLogonSelector.ClientID %>");

ddlLogin.options[1].innerText = "Internal Employees";       

ddlLogin.options[2].innerText = "External Partners";

        ddlLogin.options[2].selected = true;
    }

     

    _spBodyOnLoadFunctionNames.push("changeDropdownValues");

</script>

<div id="div1" style="display:none">

<SharePoint:EncodedLiteral runat="server"  EncodeMethod="HtmlEncode" Id="ClaimsLogonPageMessage" text="Select the credentials you want to use to logon to Extranet site" />

</div>

<SharePoint:EncodedLiteral runat="server"  EncodeMethod="HtmlEncode" Id="ClaimsLogonPageMessage1" text="Select the credentials you want to use to logon to   Extranet site" />

<br />

<br />

<SharepointIdentity:LogonSelector ID="ClaimsLogonSelector" runat="server" />

<br />

<br />

<SharePoint:EncodedLiteral runat="server"  EncodeMethod="HtmlEncode" Id="Message1" Text="Note:Employees please select Windows Authentication."  />

<br />

<SharePoint:EncodedLiteral runat="server"  EncodeMethod="HtmlEncode" Id="Message2" Text="All other users please select Forms Authentication."  />

</asp:Content>