fedex stops with the api fedex services, so you have to use the web services.
I installed this contribution: (in oscmax 2.5 rc1 and rc2)
osCommerce Community Add-Ons
it works ok, but if a customer uses special characters (like Ď,Ô,Ć,Č,ś,ĺ,...) in his address, you get error on checkout:
Fatal error: Uncaught SoapFault exception: [Client] SOAP-ERROR: Encoding: string 'pok\xf3...' is not a valid utf-8 string in /home/bram/public_html/catalog/includes/modules/shipping/fedexwebservices.php:184 Stack trace: #0 /home/bram/public_html/catalog/includes/modules/shipping/fedexwebservices.php(184): SoapClient->__call('getRates', Array) #1 /home/bram/public_html/catalog/includes/modules/shipping/fedexwebservices.php(184): SoapClient->getRates(Array) #2 /home/bram/public_html/catalog/includes/classes/shipping.php(124): fedexwebservices->quote('') #3 /home/bram/public_html/catalog/checkout_shipping.php(192): shipping->quote() #4 {main} thrown in /home/bram/public_html/catalog/includes/modules/shipping/fedexwebservices.php on line 184

I've posted already on the forum of the contribution:
FedEx - Web Services v9 - osCommerce Support Forum - Page 8

but no reaction, and there are other people having it also.

Can someone help me?

Thanks in advance.