Posts not showing in search machine after import

Hi, I’ve got a bit of a curious problem. I’ve imported several hundred posts through the MT importer. They seem to be imported alright, when I browse the archives they are displayed neatly.

But they don’t show up when I do a title search for them, both on the website and in the posts manager. So I suspect there is a database field which should be adjusted. Does anyone have a clue which I should alter?