I don't see how I could do that, I don't have a subscription, so I don't think they'll let me even look at the packages.
It says here:
The x86 "Hugemem" kernel is not provided in Red Hat Enterprise Linux 5
Try googling it, I can't find much. If you can't find it, I say get the kernel source package and compile it, there are many guides to kernel compiling. In this case try to find the original 'config' file, start with that and add hugemem support, then compile it.