Mail not allowing me to send from new Address

Question

My email got migrated over to a new host.
The original host was a pop3.  the new host is an imap.
I set the new account up on Mail, it checks out perfectly, all settings verified when I created it.  receiving email perfectly but...  when I go to send a new email, it only shows my old email account in the "from" drop down menu.  I edited the smtp server list and even removed my old account.  I also deleted my com.apple.mail.plist and let it reset the preferences...  still no luck.  My new account does not show up in the drop down "from" menu, no mater what I try, so all my new emails are showing up in my old account's sent folder.  anyone had any issue or solution for this?
thanks

Answer 1

The new account is provided by Media Temple.
all the settings are correct, i do know that for a fact, same settings are working perfectly on my iphone.
The old account and the new account are the same exact email address.  the email along with my website was migrated from Hostway, to Media Temple.
I have 4 accounts going into my Mail now.  the original one with this name, which emails I simply cannot afford to lose so I did not delete the account.  and 2 others. all of which I can see when I compose a new message in the "from" drop down menu.  The only one I do not see, is the brand new one that is the same email address as my first, but with completely different settings.  Maybe the simplest thing to do is to go change the settings on the original account to the new settings.  I was just afraid that doing so may wipe the emails from the old account.  Simply because the new imap won't see those on its server and think they don't exist... am I incorrect in that?