[CentOS] kexec for CentOS 4?

I have a remote CentOS 4 machine on a network where I can't put a DHCP or PXE server, and I want to do a complete reinstall. So what I want to do is, from the currently-running system, to invoke an installation kernel and initrd in just the same way that GRUB would, giving it a boot command line that specifies a remote kickstart file, installation tree, and other required info.

It looks like kexec is the right tool to do this, but I have only been able to find it for CentOS 5. Does anyone know where I could get kexec for CentOS 4? Does the CentOS 4 kernel support it?

If not, are there any other ways to achieve what I've described?

Thanks Tony