OK, I changed the settings recommended, and postfix is still not announcing STARTTLS, I still get the error sent back from Gmail, 'STARTTLS must be sent first', and the log files 'mail', and 'mail.err' don't show anything relating to tls.
I've always had problems with postfix, first I couldn't, and still can't set it as a closed relay (currently even though my isp block ports 25 and 110, my linux box firewall is closed to ports 25 and 110), and now, I can't set it as a local relay to send emails from a local php script (running on the same system as postfix) to a Gmail's smtp (via my Gmail account), then Gmail would route it out to a recipients address.
The error I get is when postfix receives the Gmail error and sends that error as an internal email.
Maybe I may have better results using sendmail.
The setting up of postfix, I followed the instructions here http://bookmarks.honewatson.com/2008...il-smtp-relay/
and there many other tutorials on the subject, but they are all basically the same.