The wizard can now connect workstations that are domain-joined (including workstations that are already joined to the current SBS domain - does this mean that I can assign a profile to a user after the initial run?).

Go to http://connect

Profiles Marked as Private

When you assign a profile it will not show up if the profile has been marked as private. In this case go to C:\Documents and Settings, right click on the user's folder and clear the "Make Folder Private" checkbox.

If you still can't select the profile after re-running the wizard, mark the folder as private again, and then clear the setting once more.