Lack of 301 Redirects with Posterous is Really Dumb

Posterous’ lack of any kind of 301 redirect for imported URLs is really really dumb.  For the life of me I can’t figure out how their so-called migration process could be considered finished and ready for use without this, especially since the default WordPress URL scheme is different from theirs.  Even worse, as far as I can tell, there’s no way to customize the 404 to even point users to the fact that they could go to the main domain and search for what they were looking for.