File Associations in KDE

I have many files in strange formats that can be opened by applications that are not installed by default on any Linux distribution. How do I teach KDE to recognize these files based on their endings (like .ab1) and to open them - when clicked - with the correct application? Go to Control Center -> KDE Components -> File Associations -> Add -> Leave Group "all" and type in some short, descriptive name (e.g. ABI trace file) -> Under "Filename patterns" put the file extension (or any other pattern that enables KDE to recognize the file; e.g. *.abi1) -> Write something descriptive into the "Description" field -> Under "Application Preference Order" click "Add" and type the name of the application (if it is in the path) or browse and select the executable (for the .ab1 example it would be e.g. trev, the trace file viewer from the Staden package) -> Click "Apply" -> I have the feeling that you have to log out and log in again to make the changes active. For the above example you will see that Konqueror list for files with the .ab1 ending the File Type "ABI trace file" and when you click them, they are opened with the trev application.