Thanks again to poil for the original hack. Since posting a revision, I've had a request to add this particular hack's functionality to editpost.php, previewedit.php, and the markup portions to sendprivate.php and sendmessage.php (originally, I considered adding the hack to editpost.php & previewedit.php, but considered those additions a little redundant).
I may get to it this weekend (I've been busy).
In the meantime, if you're a really enterprising individual, it shouldn't be too hard to figure out how to add the hack to the above scripts using the existing download; newpost.php, addpost.php, newreply, editpost.php, and previewedit.php all share some common code and a similar structure.
