How can I make Capital letter ( upper-case ) permalinks?

How can I make a link like this?

http://www.lifecellskin.us/Dev/About

the “Using_Permalinks” part, A is Capital letters. But WP automatically convert upper case to lower case.

I’m trying to convert an old site that made by only html to a WP platform site. Some links to the site look like this:

http://www.lifecellskin.us/About

The site is already indexed by SEO. so I don’t want to lose SE rankings.

Thanks for reading this, and hope somebody will be able to shed some light on it…

The page URLs are defined by the slugs, and by default they are formatted and lower-cased by the function sanitize_title_with_dashes(). However, this function is called via a filter, and you can unhook the filter so it doesn’t get called:

remove_filter( 'sanitize_title', 'sanitize_title_with_dashes' );

Just doing this is probably not a good idea, as it will not remove the spaces and other weird stuff in the slug. I suggest you copy the existing function, remove the part that lowercases it, and hook it up again:

add_filter( 'sanitize_title', 'wpse5029_sanitize_title_with_dashes' );
function wpse5029_sanitize_title_with_dashes($title) {
    $title = strip_tags($title);
    // Preserve escaped octets.
    $title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title);
    // Remove percent signs that are not part of an octet.
    $title = str_replace('%', '', $title);
    // Restore octets.
    $title = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title);

    $title = remove_accents($title);
    if (seems_utf8($title)) {
        //if (function_exists('mb_strtolower')) {
        //    $title = mb_strtolower($title, 'UTF-8');
        //}
        $title = utf8_uri_encode($title, 200);
    }

    //$title = strtolower($title);
    $title = preg_replace('/&.+?;/', '', $title); // kill entities
    $title = str_replace('.', '-', $title);
    // Keep upper-case chars too!
    $title = preg_replace('/[^%a-zA-Z0-9 _-]/', '', $title);
    $title = preg_replace('/\s+/', '-', $title);
    $title = preg_replace('|-+|', '-', $title);
    $title = trim($title, '-');

    return $title;
}