Just a quick guide to add kexts and make iso from OS X.
Download this package
Open terminal
Make a directory
mkdir newiso
copy following from the package into newiso:
- boot
- initrd.img
- isolinux.bin
- isolinux.cfg
- mboot.c32
to edit initrd.img set rw permission
chmod 777 newiso/initrd.img
then you should open it
hdiutil attach newiso/initrd.img
now copy the kext you need into /Volumes/initrd/Extra/Extensions/
cp -R mykext.kext /Volumes/initrd/Extra/Extensions/
I suggest you add dsmos.kext NVkush.kext and if you have alc889 also HDAenabler.kext and if you need kext to boot your root device also
One thing to notice, the kexts need this in the info.plist file:
<key>OSBundleRequired</key>
<string>Root</string>
or
<key>OSBundleRequired</key>
<string>Console</string>
or they will not load. To add those properties you can use nano and need to be added at the end of the plist file just before the last lines:
</dict>
</plist>
If you need a bigger image you may resize it with this comman, choose appropriate size
hdiutil resize -size 20MB newiso/initrd.img
when you are finished adding you eject your initrd image
hdiutil detach /Volumes/initrd
now you need to create your iso
hdiutil makehybrid -o new.iso newiso/ -iso -eltorito-boot newiso/isolinux.bin -no-emul-boot
and then burn new.iso with your favorite burner (first try with a cd-rw disc so you can redo it later iwthout wasting cdr disc)