[wp-hackers] Customize error on empty comment

[Dino Termini]

Hi all, I'd like to know if there's a way to customize the default error 
message (wp_die) shown after an empty comment is submitted. I tried to 
filter this adding a javascript that prevents empty form to be 
submitted, but it's not enough of course. Is there a way to override the 
wp_die function through some kind of hook?

Thanks in advance,
camu.