The 'SAY' option doesn't work in PXE configuration with UEFI system

Issue

• We are using pxeboot configuration with UEFI systems.
• When attempting to boot, We are not able to use the 'SAY' syslinux option.
• When using legacy BIOS this option is parsed without issue.
• We are able to PXE successfully, and has configured his system to boot with the following:

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s1-netboot-pxe-config-efi.html

• When placing the SAY option in the efidefault file or the mac specific address file, the command looks ignored. The title and other options show up normally.
• This is our configuration. That looks correct.

default=0
timeout=0
splashimage=(nd)/banner.xpm.gz
hiddenmenu
title Linux
    root (nd)
    SAY Hello world....
    kernel /rhel64/vmlinuz
    initrd /rhel64/initrd.img