outgoing.pl is only used to send bounces, auto-replies and forwarded accounts. Other mail (ie. Compose => Send), is sent immediately using whatever method the admin has set (sendmail or smtp).

There's one thing I want to clarify with you. Is your Gossamer Mail set up to use a smtp server to send mail (Setup => Outgoing Email => Configuration => SMTP Server or Sendmail Path)? If so, is that the same smtp server that you're using in Outlook?

Adrian