Better support for more replacement of special charactes in URL

Currently when you post the url is the title/subject.
But if your blog is in another language than English there are great chances this becomes an issue to you:
Texts like “felicitación de cumplea?os” becomes “felicitacin-de-cumpleaos”.

Currently, its removing special characters from the url, nice, but it could be much nicer:
I suggest:
Replace á, ?, à as: a
Replace ? as n
(and such..)

So in the example above, the url would be “felicitacion_de_cumpleanos”, much nicer.

In short: replace special characters for the related acceptable character in url’s.