Dear Maintainer,
On the auto-detecting create account dialog, the servers display like the attached screenshot.
Note that although IMAP is a drop-down, the fact that the server name starts with . implies that the overall server is:
IMAP.test.com
For my real account, it didn't work, so I had to click Advanced config.
However, this really puts .test.com in the Server Name (which obviously would never work), rather than imap.test.com (which the GUI implies, and could work).
A screenshot is http://i.imgur.com/zDqW0.png .