dealing with two email accounts that use the same SMTP (outgoing) server

Folks:

re: mail.app 5.2 (MacOS 10.7.4) with respect to POP accounts only

I've read this thread multiple times, spent many hours experimenting, and my web searches haven't come up with any more useful help.

How do you persuade mail.app to accept settings for two similar, but distinct email accounts that use the same SMTP (outgoing) server? Say, the accounts are "blue.example.com" and "green@example.com". These have different user names and passwords. The SMTP server is "smtp.example.com".

I think this is the appearance of success: the SMTP Server List (as seen in edit-the SMTP-Server-List mode) shows:

Server Name In Use By Account

------------------- --------------------------------------------------------------------

...

smtp.example.com blue@example.com, green@example.com

...

(Description column omitted for brevity. And of course, mail.app doesn't show the little envelope icons.)

But I cannot reliably achieve this result. When I select the SMTP server from the list for the second account --as suggested in the above-referenced thread--- I see the credentials (user name and password) for the first. Should I overwrite them? No, I don't think so -- I think that will break the first account. I feel mail.app should present me with empty credentials boxes instead. Maybe this happens -- sometimes. But I can't see how to make it happen. Am I simply overlooking something?

A slightly different way of asking about this issue: Suppose I manage to do a proper setup for the two accounts and they work. Then I change the password for "blue@example.com" on the server. What is a reliable way of reaching the SMTP credentials for that account to make the edit? Same question for "green@example.com"? Even when I successfully attach two accounts to one SMTP server, I seem only able to reach the first listed one to make changes. (In this case, "blue.example.com").

It is possible I'm missing something incredibly obvious... I know the credentials for each account are distinct, but maybe mail.app copies them from the POP (incoming) settings. Nah, that can't be, can it? Or what?

Maybe I'm seeing bizarre things due to scrambled mail.app preferences. I've seen it before on other apps: delete the current preference file, get an auto-generated fresh one, and sanity returns. But with mail.app, with the prospect of losing years of emails --yeah, I've done it-- I'm extremely reluctant to mess around.

Suggestions, please.

TIA

Message was edited by: Hen3ry to clean up the table a little and add a parenthetical explanation.