Regadring problem to set config in the Hardware & Power-menu, which basically means you can't config your UPS, I found out the problem.
If you look at the web trafic when you open the menu (Synologs normal web page, control panel-page), you see that the http response is a 500 (not a 200 OK), and you actually get a "Sorry, the page you are looking for is not found"-page back from the Json-request, which of course is ignored. Looking at the request, and trying to remove different part of the json-object thats sent as a parameter, I found out that its SYNO.Core.Hardware.FanSpeed part thats causing the problem. If you remove that, and send the post again, it will return OK.
If you look in the /var/log/message file, you will see this entry for each http-request
Jan 4 21:36:11 DiskStation entry.cgi_SYNO.Core.Hardware.FanSpeed[1].get[32445]: external/external_fan_adjust_config_full_speed.c:90 Cannot find HIGH fan table.
Right about here is where my Xpenology knowledge ends. Something is wack with the Fan settings/config/control, and since it can't get all the details to open the page, you can't edit the page correctly.