Yes you need to edit the java of the pos software or basically the java bean. You can look at the manual given with the device or you can just look at the basic java bean of the software program over the web for the coding and get it matched with yours and edit it accordingly.
Same issue although valor. required doesn't work for tthis function and breaks more source code.
I am unable to reproduce this error. Would you be able to get the exception that is thrown? Should be in the dos window created by the app.