Here\'s my Init script which I have at my Ubuntu workstation. I need to run a command as another user than root, but I just can\'t get my head around how it should be done. Neit
su is probably a more universal approach, but this is also possible on some common distributions with sudo:
sudo -u $MUSER $COMMAND $ARGS
(just reread your question and didn't realize that doesn't work for you, but it has worked for me in init scripts)