How to replace a Stunnel with a Haproxy

Question

I try to replace an existing Stunnel configuration

sslVersion = TLSv1.2
ciphers = AES256-SHA:AES128-SHA:RC4-SHA:RC4-MD5
CAfile = acs.pem

output = stunnel.log
debug = 7

[CONF1]
verify = 2
cert = conf1.pem
key =  conf1.key
accept = 0.0.0.0:<port_conf1>
local  = <hostname>
protocol = connect
protocolHost = <target dnsname>:443
connect = <haproxy to go outside>:<port>
client = yes

with an Haproxy

does it possible ? If no i would like to understand why please :-). Thanks

I tried without succes

frontend front_wtf
    bind *:<port_conf1>
    option httplog
    stats  enable
    mode http
    default_backend back_conf1

backend back_conf1
  mode http
  stats  enable
  http-request set-header Host <target dnsname>
  http-request set-header X-Port 443
  server conf1 <haproxy to go outside>:<port> ssl ca-file ./acs.pem crt ./conf1.pem.key