HAproxy and Node.js+Spdy

I'm currently using node spdy to serve files. This works beautifully.

However I would like to use HAproxy to load balance amongst these node servers. But when my node/spdy server is behind HAproxy, request.isSpdy is false... so spdy is all of a sudden not supported?

Here's my HAproxy configuration: global maxconn 4096

defaults
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms

frontend http_proxy
    mode http
    bind *:80
    redirect prefix https://awesome.com code 301

frontend https_proxy
    mode tcp
    bind *:443
    default_backend webservers

backend webservers
    balance source
    server server1 127.0.0.1:10443 maxconn 4096
    # server server2 127.0.0.1:10444 maxconn 4096

Thanks!