How do I require users to tag post in blog ?

[maneri]

I need users to always set a tag before posting in blog. I have created a new plugin with this functions and hooked it in blog_post_start inside blog_post.php

PHP Code:

if(isset($_POST['sbutton']) && empty($_POST['taglist'])){
echo "You must enter a tag in order to post your thread";
die();
} 


It works perfectly, I just would like to change echo, I do not want users to get a simple browser page with that simple message "You must enter a tag in order to post your thread".

Rather I would prefer an errors function similar to the one users get when, e.g., they do not put any title in theit blog entry.

What should I put after if(isset($_POST['sbutton']) && empty($_POST['taglist']))
in order to get en error like this ?



Thanks !