When I try to use a command block to summon mob/player heads through falling sand, it gets placed as plain sand instead.

I understand that objects like mob heads require orientation which is not possible with falling sand yet, but when i try to summon a mob head through falling sand, it summons normal sand instead. I am trying to build a cool dance game that requires mob heads to be changed through falling sand, but it would be greatly appreciated if mob heads at least fell a default direction and i had to build my machine around that. Thank you and great job with 1.7 by the way!