Beaker currently doesn't support generating a menu for EFI GRUB, only for PXELINUX's menu.c32. The menu you are seeing was probably generated by Cobbler, which explains its age (Cobbler was switched off in our labs around June 2012).
We can convert this to an RFE for Beaker to generate an EFI GRUB menu. It shouldn't be too hard, given that we already have the code for menu.c32.
If you can point us at some docs for the file format EFI GRUB is expecting, that would really help. The last time I looked at EFI GRUB it was completely undocumented which meant there was a lot of frustrating guesswork trying to figure out exactly what it wanted.
Patch is on Gerrit: http://gerrit.beaker-project.org/2496
At present the patch works, in the sense that it produces a listing in /var/lib/tftpboot/grub/efidefault which looks sane, but I haven't been able to test it against any real hardware.