Replace Build Iso which comes with RHEL Sat 6

I am having problems with booting using the RHEL Sat 6 - Generated boot ISO. I would like to replace it with my own which my company has been using for multiple years and works great on all our hardware.

I was hoping someone could tell me how where the scripts where to make this change (I see the one that generates the boot config file but not how to replace the actual binaries)

If I open the Generated boot CD these are the existing files

.
./boot.cat
./ipxe
./isolinux.bin
./isolinux.cfg
./script

I want to add/replace with these files

.
./images
./images/efiboot.img
./images/efidisk.img
./images/install.img
./images/product.img
./images/pxeboot
./images/pxeboot/initrd.img
./images/pxeboot/TRANS.TBL
./images/pxeboot/vmlinuz
./images/TRANS.TBL
./isolinux
./isolinux/boot.cat
./isolinux/boot.msg
./isolinux/grub.conf
./isolinux/initrd.img
./isolinux/isolinux.bin
./isolinux/isolinux.cfg
./isolinux/memtest
./isolinux/splash.jpg
./isolinux/TRANS.TBL
./isolinux/vesamenu.c32
./isolinux/vmlinuz
./mkbootcd.sh
./TRANS.TBL