Golang SSL TCP socket certificate configuration

I'm creating a Go TCP server (NOT http/s) and I'm trying to configure it to use SSL. I have a StartCom free SSL certificate which I am trying to use to accomplish this. My server code looks like this:

    cert, err := tls.LoadX509KeyPair("example.com.pem", "example.com.key")
	if err != nil {
		fmt.Println("Error loading certificate. ",err)
	}
	trustCert, err := ioutil.ReadFile("sub.class1.server.ca.pem")
	if err != nil {
		fmt.Println("Error loading trust certificate. ",err)
	}
	validationCert, err := ioutil.ReadFile("ca.pem")
	if err != nil {
		fmt.Println("Error loading validation certificate. ",err)
	}
	certs := x509.NewCertPool()
	if !certs.AppendCertsFromPEM(validationCert) {
		fmt.Println("Error installing validation certificate.")
	}
	if !certs.AppendCertsFromPEM(trustCert) {
		fmt.Println("Error installing trust certificate.")
	}

	sslConfig := tls.Config{RootCAs: certs,Certificates: []tls.Certificate{cert}}

	service := ":5555"
	tcpAddr, error := net.ResolveTCPAddr("tcp", service)
	if error != nil {
		fmt.Println("Error: Could not resolve address")
	} else {
		netListen, error := tls.Listen(tcpAddr.Network(), tcpAddr.String(), &sslConfig)
		if error != nil {
			fmt.Println(error)
		} else {
			defer netListen.Close()

			for {
				fmt.Println("Waiting for clients")
				connection, error := netListen.Accept()

I've tried switching around the order of the certs, not including some certs, etc. but the output from openssl s_client -CApath /etc/ssl/certs/ -connect localhost:5555 remains essentially the same, verify error:num=20:unable to get local issuer certificate. See <a href="http://pastebin.com/hALjVZb3">here</a> for full output. I seem to be doing something wrong with the intermediate certificates, but I have no idea what. I have been working on this for a few days, lots of googling and SO'ing, but nothing seemed to quite fit my situation. I have set up many certificates in Apache and HAProxy, but this really has me stumped.

The RootCAs field is for clients verifying server certificates. I assume you only want to present a cert for verification, so anything you need should be loaded into the Certificates slice.

Here is a minimal example:

cert, err := tls.LoadX509KeyPair("example.com.pem", "example.com.key")
if err != nil {
	log.Fatal("Error loading certificate. ", err)
}

tlsCfg := &tls.Config{Certificates: []tls.Certificate{cert}}

listener, err := tls.Listen("tcp4", "127.0.0.1:5555", tlsCfg)
if err != nil {
	log.Fatal(err)
}
defer listener.Close()

for {
	log.Println("Waiting for clients")
	conn, err := listener.Accept()
	if err != nil {
		log.Fatal(err)
	}
	go handle(conn)
}

Even though you're not using HTTPS, it may still be useful to walk through the server setup starting at http.ListenAndServeTLS.