Hello and welcome to LinuxQuestions,
I have to modify kickstart a lot for our install images at work and never used the createrepo command, nor changed the xml files. I just create a directory with our packages, add, delete, modify as how I see fit and install them without a problem. Have a look at this post in another recent thread regarding kickstart
. There you'll notice how I mount the DVD and copy the contents from it and next install it with rpm. Have fun with Linux.