WordPress MU

This is what I would like to do. I have a an author who wants to set up his blog so that every time he posts, some specific information appears at the bottom of his post. This includes his LinkedIn profile button and some about-the-author information. Trouble is, he doesn't want to manually add this himself, and he wants it to be retroactive to several hundred other posts. Naturally, I don't want to hack the single.php or even the index.php pages so this this one author's stuff appears on everyone's posts. And most authors will want none of this.

Any advice for plugins? My eyes are crossed looking for something that will do this.

Thank you in advance ...

Someone asked pretty much the same question yesterday oddly enough

Yeah, there's a post signature plugin out there. Check the wp.org repository. I use one on a client site and can dig it up if you can't find it.

SteveAtty: This one? http://mu.wordpress.org/forums/topic.php?id=11781

Andrea_r: I'll try to find it and let you know if I don't.

UPDATE: going to "wp.orp" proved fruitless.

http://www.dagondesign.com/articles/add-signature-plugin-for-wordpress/