To put a script in rc.[X], is usually a link, but more important is the name. The name must be S or K with numbers. That tells init where in the runlevel to run its script.
Example, S10network means that as rc3 goes through the start scripts, they are sorted by when the start, lowest starting first. If There are multiple scripts with the same number like S10, they are next sorted alphabetically. S10a starts before S10z.
Also look at chkconfig. If your script is correctly configured then chkconfig will create all of the links in the rc levels.
Look at the line #chkconfig in one of the scripts in init.d. Copy that line to your script then type chkconfig --add {script name}.