I have a similar setup at home. I got myself a mail server and configured it to relay outbound messages from the i only (to a pc on my LAN). This is then relayed to my hoster in the USA. The software is Mercury and it is freeware - if you are using for business purposes, then it shareware (I think 90 days free). I also then downloaded NO-IP (freeware) to cater for the dynamic DNS. Didn't have to do anything fancy on the i and it works wonderfully. I am not at home now, but can have a look at how I set it up and let you know if you need it.