Permitting UTF-8 alphabetical chars

[eluser]cb951303[/eluser]
well, my site does a database search with the keyword taken from the URI but according to this:

Code:

$config['permitted_uri_chars'] = 'a-z 0-9~%.:_\-';

I can't include chars like 'ç', 'ş', 'ğ', 'ı' or any other non ascii utf-8 chars in the URI.
is there a solution to this?

or am I just not supposed to use URI to pass search keywords ?

thanks very much