In the window that opens up, select Edit > Mail & Newsgroup Account Settings, as is shown in the picture below.
In the dialog that shows up, create a new mail account by selecting Add. In the dialog that comes up, highlight Email Account and select Next >. In the next window, enter the following information, as is shown below:
Select Next > to confirm your entry, and in the dialog that pops up, enter the following server information:
Once you have entered this information, click on Next > and ensure that your the following information is correct:
Click Next > to accept your entry. On the final page, ensure that all of the information is correct and then click on Finish to finish creating your account.
You are now almost done. First, though, click Server Settings option under your new account, and enter 1143 as the Port, as is shown below:
Lastly, click on the Outgoing Server (SMTP) and enter the following information, as is shown in the picture below:
You are now done setting up your account. Click on OK to close the Mail & Newsgroup Account Settings window, and you should be able to use your new ePOST account.