Run Script from DialogButtonMenu.xml

I run a Raspberry PI 2 with a RemotePi from msldigital. So everything works fine but the shutdown via UI won’t work.
I created a script which is working when i run it manually.
So i tried to link it with the DialogButtonMenu.xml of the confluence skin which i’m using.
i Substituted the comand:
as described here
but when i use the Powerdown button on the UI nothing happens
may someonecan help me.

greez schinni