"So you want a facebox that shows a form which does an asynchronous submission and updates the facebox with the results of the submission showing error or success messages." Yes, I do. This worked. Thanks, Wes Gibbs.
It's a guide to Dudley in SSF4. Looks like a good one, and, given it's a few years since I've played Dudley (and that was in a different game)… much welcome. To read in the near future.