Hi all,
is anybody know, how I can include my own script files directly in OpenWRT firmware when compiling it? I had try several times, but without any luck .

Thanks.

Files you put into <kamikaze_directory>/files get included into your firmware.

Take a look at the ImageBuilderHowto in the wiki Section 3.4.  It works the same way with buildroot, for example here is a list of my custom files which replace the default sysctl.conf, firewall, and netconfig.  I also add an additional hotplug script.

~$ find kamikaze_7.07/files/
kamikaze_7.07/files/
kamikaze_7.07/files/etc
kamikaze_7.07/files/etc/sysctl.conf
kamikaze_7.07/files/etc/init.d
kamikaze_7.07/files/etc/init.d/firewall
kamikaze_7.07/files/etc/init.d/netconfig
kamikaze_7.07/files/etc/hotplug.d
kamikaze_7.07/files/etc/hotplug.d/iface
kamikaze_7.07/files/etc/hotplug.d/iface/20-fprobe-ulog