Customize Ubuntu syslinux CD Installation menu options

I wonder to remove Function options from syslinux on Ubuntu CD installation iso.

I am customizing my own distro and I want to remove those options which are useless for my case.

I have tried changing .cfg files but doesn’t work and I can’t find proper setting to remove it. I succeed on changing background and some colors, but not customizing these options.

Options to be removed from custom syslinux