We've moved on, you should too.
Funny, thought I was trying to be helpful.
I currently have 143 and 993 set for my IMAP account. My server is bigbox.COMPANYNAME.com and that is the same for both income and outgoing--not smtp. The mail sets up easily on my iphone and ipad, but not on my computer. I even tried thunderbird and that doesn't work.
Pay no attention to that man behind the curtain. Check and see if your outgoing mail server requires authentication (even though its the same server, the Virtual Servers used in Exchange 2003 can have different settings).
If you have access to your Exchange server,
1. Open Exchange System Manager
2. Open your first administrator group
3. You should see Servers
4. Under servers, navigate to SMTP
5. Right click on Default SMTP Virtual Server, and go to Properties
6. Click Access
7. Click Authentication
What are the settings here? If Basic authentication is required, you will need to "Use the same credentials for your Outgoing Server as your Incoming Server" This should be a setting in your mail app. If TLS is required, use SSL.
If you do not have access to your Exchange Server, you will need to contact an admin or just enable/disable the settings listed above in your client. You may find something that works.