In case you don't like the idea of using SOAP or run into technical problems with it, but you still would like to use the web service, you can call exactly the same functions using an http or https interface. You send the values for SOAP parameters, along with the name of the desired function, to the following form, using GET or POST:
https://ssl.ibanrechner.de/http.html (or without SSL: http://ssl.ibanrechner.de/Riban/http.html).
The server will forward this request to the SOAP interface https://ssl.ibanrechner.de/soap and respond with an XML file whose structure reflects that of the corresponding SOAP response. If you would like to have your request forwarded to a specific version of the SOAP interface, for instance the version https://ssl.ibanrechner.de/soap-12-2, please specify the version (here: "12-2") by using the additional parameter "version", for instance by adding "&version=12-2" to your URL.