HabPanel Umlaute on QNAP

When running OpenHab on a Windows machine I can set the
System Variable “JAVA_TOOL_OPTIONS” to “-Dfile.encoding=UTF8” and text in HabPanel is displayed correctly for my language german (äöü …)

Now I transfer my OpenHab setup to a QNAP NAS and everything runs as expected (currently using JRE 8.144). Only the äüö are not displayed. Has anyone an ide how to ste the cariable on my QNAP NAS like it is done on my Windows machine?

any idea appreciated!


is there no one why can help?