The seb site says, on the e-mail setting page, to use port 1025. When it didn't work, I tried the standard, port 25 and it does work.
Also, I think that it is a little obscure to get to you e-mail box when using web mail by clicking on "edit Website." I would suggest that there should be an e-mail option similar to "Web Hosting" on the menu bar at the top of the page. That could lead to different pages depending on whether the customer is using e-mail forwarding or e-mail hosting.