How about filenaming/headline

I tried few ways to get it working. I came up using my own headline because this will be the product name. But as I have foreign characters in my headline / product title, files uploaded by ftp get after processing the headline / product title as filename. Spaces are replaced by “-” but foreign characters are not replaced: a “ü” should be replaced with “ue” as WordPress by default does. Any ideas how to solve this?