public override void ProcessSignInRequest(Scope scope, HttpContextBase httpContext)
{
var samlRequest = new AuthRequest(MultiProtocolIssuer.ReplyUrl.ToString(), _issuer, _audienceRestriction, _requestedAuthnContextComparisonMethod, _authnContextClassRefs);
var preparedRequest = samlRequest.GetRequest(AuthRequest.AuthRequestFormat.Base64 | AuthRequest.AuthRequestFormat.Compressed | AuthRequest.AuthRequestFormat.UrlEncode);
var returnUrl = GetReturnUrlQueryParameterFromUrl(httpContext.Request.Url.AbsoluteUri);
httpContext.Response.Redirect(string.Format("{0}?SAMLRequest={1}&RelayState={2}", _identityProviderSSOURL, preparedRequest, returnUrl));
httpContext.Response.End();
}