HAProxy for VMWare Horizon Connection servers


I would like to run the 2 Horizon connection servers behind the LB, but as far as I know, only source balance algorithm will do the job, since I have to authenticate and there is no cluster mode, right?

I’ve tried this:

backend 3dcloudtest_ssl_back
  mode http
  balance source
  option httpchk  HEAD / HTTP/1.1\r\nHost:\ 3dcloudtes
  retries 2
  timeout connect 5s
  timeout server 31s
  server hor-conn01 check inter 5s fall 4 rise 3 ssl verify none
  server hor-conn02 check inter 5s fall 4 rise 3 ssl verify none

but if my connection is sent to server hor-conn01 and then it fails, I am redirected to hor-conn02 and I need to reauthenticate, but the problem is also that when hor-conn01 comes back online, I am redirected back to hor-conn01 having to reauthenticate once more. How could I avoid this las redirection?