var stsEndpoint = ConfigurationManager.AppSettings["EndPoint"];
        var relayPartyUri = ConfigurationManager.AppSettings["RelayPartyUri"];
        EndpointAddress epoint = new EndpointAddress(stsEndpoint);
        var factory =
            new WSTrustChannelFactory(new UserNameWSTrustBinding(SecurityMode.TransportWithMessageCredential),
                epoint)
            { TrustVersion = TrustVersion.WSTrust13 };
        if (factory.Credentials != null)
        {
            factory.Credentials.UserName.UserName = @"systemdomain" + userName;
            factory.Credentials.UserName.Password = password;
        }
        var rst = new RequestSecurityToken
        {
            RequestType = WSTrust13Constants.RequestTypes.Issue,
            AppliesTo = new EndpointReference(relayPartyUri),
            KeyType = WSTrust13Constants.KeyTypes.Bearer
        };
        var channel = factory.CreateChannel();
        var token = channel.Issue(rst);
        var genericToken = token as GenericXmlSecurityToken;

var token = channel.Issue(rst);