private void CreateFederationContextFromConfiguration()
{
var realm = FederatedAuthentication.FederationConfiguration.WsFederationConfiguration.Realm;
var returnUrl = FederatedAuthentication.FederationConfiguration.WsFederationConfiguration.SignOutReply;
federationContext.OriginalUrl = FederatedAuthentication.FederationConfiguration.WsFederationConfiguration.Issuer + "?wa=wsignin1.0&wtrealm=" + HttpUtility.UrlEncode(realm)+ "&wctx=ru%3d" + HttpUtility.UrlEncode(returnUrl);
federationContext.Realm = realm;
federationContext.Context = "ru%3d" + returnUrl;
}