Well there ya go,BOOTCAMP assistant repartitions the drive in hybrid MBR/GPT manner, so even though it is a GPT drive it appears to Windows as a MBR partitioned drive and WIndows can not see the EFI/ESP partition, therefore can not boot in UEFI mode. This hybrid MBR/GPT is not supported by OC. OC will only boot Windows loading the boot drivers and the BCD store from its ESP/EFI partition.
thanks for the help.