You could set the traveling user up with a GMail account and forward all the SME email to that account; you can set the GMail account to use the SME email address as the reply address so his recipients won't even know the difference. If your user isn't comfortable with GMail you can set up his/her email client to use POP3 with GMail after making the appropriate settings change in GMail.
Other solution: have user establish VPN connection to SME server, then download email as normal.
Other other solution: I think it's possible to allow POP3 access from the Internet but don't know the exact commands.