i realise that. I no longer need the relationship. The post on the main blog is what I need, but the permalinks are screwed up.
And now here’s something new I just learned: When the post with the bad permalinks tweets using wordtwit or what have you, it tweets the correct permalink, and the post is there.
So the problem is that posts exist on a page with the correct permalink — they are at year/postname. But the links that the site uses are wrong, i.e., the one that’s on the edit page, postname.