Hi!
I'm running KMail 2.1.1 on a Slackware64-current box, out of Alien Bob's KDE SC 4.6.5 packages and 4.6.1 KDE PIM packages. Akonadi is 1.5.3.
I've tried to rationalize a bit my mail organisation, as I have 5 different mail addresses for different purposes and decided to create KMail maildirs for each. For three adresses, I was already using specific first-level subdirs to sort my mails, so changing them to actual maildirs and removing the top one actually worked out well, though with a bit of hand work.
However, I now try to create a new maildir to receive mails for a new address, and I can't work things out right now. I create the KMail maildir in the KMail configuration window without any problem and it appear as ready in KMail and in the Akonadi configuration screen.
But it doesn't show up in the folder list in the left column of KMail.

On top of that, though I can create subdirs in the Local mail folder, but I cannot do that in any of the maildirs I created. The option is greyed.
Is this a known issue or shall I report as a bug?
Or is there anything wrong in the way I try to use the software?

I just upgraded to KDE SC 4.7.0, on top of akonadi 1.6.0, and the same problems still apply.

You could check if the folders on the HDD are actually created correctly. That means not only FOLDER/{cur,new,tmp} must exist but also .FOLDER.directory (which I guess can be empty, but {cur,new,tmp} won't surely hurt).

FOLDER=MyMailAccount
mkdir -p ~/MyMaildirs/{$FOLDER,.$FOLDER.directory}/{cur,new,tmp}

M