problem with start-stop-daemon and --exec

[Ed W]

Hi, I see a difference in behaviour between "real" start-stop-daemon on 
gentoo and busybox version.  Specifically nginx renames it's parent 
process commandline name:

# cat /proc/`cat /var/run/nginx.pid`/cmdline
nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf

However, I can stop it without a problem on "real" start-stop-daemon
# start-stop-daemon --stop --exec /usr/sbin/nginx --pidfile 
/var/run/nginx.pid


However, using busybox start-stop-daemon I get an error

$ start-stop-daemon --stop --exec /usr/sbin/nginx --pidfile 
/var/run/nginx.pid
no /usr/sbin/nginx found; none killed


Can anyone please help with a fix?

Thanks

Ed W