Scenario:

Dell R420 configured for UEFI boot.

Xen Dom0 server option selected in Installation.

At Partitioning:, selected Whole DISK, and LVM with separate /home.

Back at the Installation Selection page, I see the message: "Because of the partitioning, the bootloader cannot be installed properly.

I went past this the first time around, and the system booted to the non-Xen kernel. When I tried to update ELILO, it seems that elilo does not like the Xen stanza of the /etc/elilo.conf file because of the "vmm = xen.efi" line.