WordPress MU

Well, the problem is with 2 characters
¡
and
¿

I hve a blog in spanish, and when you use exclamation or interrogation marks you do it like this
¿Como estas?
¡Muy Bien!

(How are you?
Very Good!)

And, for the ¡ mark, appears %c2% in the title (permalink)
Like this
http://kyl.cl/klog/sea-como-los-famosos-%c2%a1ayudenos/
but is better to be like this
http://kyl.cl/klog/sea-como-los-famosos-ayudenos/
(I edited manually)

Where can i fix this little problem?

I have wordpressmu 1.3
(but i think this can also happen in wordpress 2.3)

In order to change this behaviour you have to modify sanitize_title_with_dashes function (wp-includes/formatting.php) or write a plugin that replaces it.

You may want to check the plugin [1] I wrote sometime ago for WordPress.

[1] http://svn.buayacorp.com/misc/wp-permalink-fix/permalink-fix.php