"You have not created a /boot/efi partition" is prompted when it's tried to install Red Hat Enterprise Linux 6 on BIOS RAID with UEFI

Issue

• "You have not created a /boot/efi partition" is prompted on installation of Red Hat Enterprise Linux 6.
• The system has a BIOS RAID (RAID1), and UEFI is enabled on BIOS.
• I created custom layout include "boot/efi", "/" and "swap". (not /boot)
• This issue was not observed with auto-partition
• This issue was not observed when install RHEL6 on non-RAID HDD