Eureka, I fixed the problem.

I think it might have had to do with the redirect code being outside of the if() statement, not sure.
I've modified the code so that it will do a page refresh regardless if it's via the quick reply box or advanced reply page. The trick was to set ajax to false, and also I moved the redirect code where it edits the reason. I also modifed it to check just based on userids instead of names, then ids again...
I also had it update the post time when a double post occurs, so that the thread shows as new to people.
NOTE: I've stripped some bits of code out from Andreas' plugin, like the time checking. So compare the code before implmenting to make sure you have the features you want.
EDIT - I've had to remove the code, found a little gitch... will repost once its fixed.
EDIT AGAIN - Well, after trying many things out, I finally determined there is really no way to do it without editing some files or (partially) disabling AJAX.
I did find one little bug in the product xml...
The plugin for
postdata_postsave
It shows
$vbulletin->url for the redirect, but since its inside a class, it should use
$this->registry->url instead. I believe that was my problem with it showing "this forum is not accepting new posts" error when you try to double post via the advanced reply.