url case sensitivity

[eluser]Sy[/eluser]
OK, in an effort to identify this further I've done the following;

downloaded a new instance of codeigniter and unzipped into my directory "casetest" in the root of my Apache 2.2 www directory

I can now access the welcome page now via

http://localhost/casetest
or
http://localhost/CASETEST

great. I've then simplified my .htaccess to the following;

Code:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond $1 !^(js|css|images|robots\.txt)

RewriteRule ^(.*)$ index.php/$1 [L]

I've then added the following to my welcome.php controller

Code:

public function testing()
{
  echo 'i got to testing';
}

and thats all i've done. so its as close to vanilla as i can get it.

so now,
http://localhost/casetest/Welcome/testing
return 'my i got to testing'

but

http://localhost/CASETEST/Welcome/testing

returns me a 404 error generated by code igniter ( with formatting etc )

I'm sure i'm doing something unbelievably stupid somewhere for a vanilla install to fail soo quickly but i'm completely lost as to what..?