do you still remember your own question asked here
, almost one year ago, and the replies given?
Just like Davie already suggested, it is NOT necessary to dedicate a separate RAID1 to the MBR boot VD. Instead, you just define one smaller and one (or more) bigger VD on the same RAID10.
Of course, your configuration with a separate RAID1 does work as well, but you already noticed that.