I added one start script in /etc/rc.d/rcx.d/Smyscript.
In Smyscript, I started some daemons, some are real daemon writtten in
C code, some are really shell scripts put in background (let me refer
this one as backgrgound process after ). I noticed that the real
daemons stay, but the background processes are always killed after
Smyscript finished.

Is it supported to be that way, or my kernel configuration is wrong?