use external smtp connection?

[infor_gsc]

Hello, I have installed Zimbra succesfully in a local server.

I have mail accounts (user@mycompany.com) from hosting arsys.es.
We send and receive a lot of emails but don't want to pay for more extra space. So we use email as pop3 but the problems it's that we can't connect and see all mails from another pc or phone.
My idea is to connect this accounts with outlook using zimbra as server so mail will be available from every computer you connect.

I configured an account with pop3 in zimbra and configured outlook succesfully.
The problem is configuring smtp, i can't get it works.

Summary: Outlook sends mails with arsys.es as now we are working, but throught zimbra, saving all mail in local server.

It's hard to explain, if some can help me. Thanks.

Greetings