boot – Generate uefi signature keys for xcp-ng

I am trying to install xcp-ng on a new server, with uefi mode enabled (I am upgrading from a previous install, so uefi is mandatory)
unfortunately, my new server does not recognize xcp-ng 8.x signatures. I’ve searched and found that these signatures can be generated and installed in the bios – however, I am a bit at loss as to what executable should I use.
Here are the various efi file on the iso:

./boot/efiboot.img
./boot/gcdx64.efi
./boot/grubx64.efi
./boot/memtest.efi
./EFI/xenserver/grubx64.efi

Any help regarding this project ?

Thanks
J.