I found on my Raspberry the ZWave binding JAR in the following directory:
openHAB-userdata/tmp/kar/openhab-addons-2.5.8/org/openhab/addons/bundles/org.openhab.binding.zwave/2.5.8/org.openhab.binding.zwave-2.5.8.jar
@chris
a) Can I just modify that jar (while openhab is not running)?
b) Or do I have to uninstall the zwave binding through PaperUI first. Then modify that jar and the put it into the /addons Folder openHAB-sys/addons as described in the Tutorial “Modify a zwave binding jar to add/change a zwave device while waiting for a build”?
(@apella12 : Thank you for mentioning that Tutorial)
c) Do have to use the script as mentioned in this Tutorial “Zigbee and zwave manual install script” (This Tutorial is mentioned in one of the comments in the above tutorial)?
By the way, in the Zwave Binding JAR I found the XML files in the folder “ESH-INF/thing” 
As written in the ticket in the database, it seems, that I currently have not yet the needed access rights to download the xml-file or I am maybe just blind and don’t see the download button?
Thank you
Michael