Well..... I don't think this is really gonna make you happy:
But in 10.2, I only got that away by deleting the prefs of my mail (~/Library/Preferences/com.apple.mail.plist)
This trashes your account settings on the whole, but it shouldn't delete your personal mailboxes.....
One thing: In Panther's mail you can just easily edit the SMTP-server list.... Just as you would expect it to!
To be safe, maybe wait till 10.3? I'm sure its not hazzardous, at the moment 🙂