checkout on webshop European characters

Hi, On a oscommerce shop with a modified checkout, we have a problem with european characters. With the account creation there are european characters éàè used in the name. These characters are correctly saved in the database. When the customer comes again to the webshop, they can login with the previous account. This is no problem, but when the address is shown on the screen, the european characters are not properly shown. Also the check for the validation with a regular expression isn't working at that moment. If you want to see the problem, I can send a login ans password for the shop via the PMB.