[Exim] SMTP proxy on a different port

Hello,

I am using exim (3.36-9) on a Debian Woody system and have a problem with
its configuration.

I want to use my ISPs SMTP proxy server which runs on any port I want,
e.g. 443 and uses SMTP authentication.

I configured exim like this:

smarthost:
driver = domainlist
transport = remote_smtp
route_list = "* my.smtp.server.com:443 bydns_a"

remote_smtp:
driver: smtp
authenticate_hosts = my.smtp.server.com

login:
driver = plaintext
public_name = LOGIN
client_send = ": username : password"

How can I setup exim to use another port to deliver mails to?

TIA, Harry