You can form a Battle Company with the three detachments it takes to form it. The same with the Decurion. Please PM with specifics...or go unbound...but come to have fun!
Your instructions say 2 detachments though...
Wargamescon 40k Judge
caldera40k.blogspot.com
Hogleg - "only in my head someone bought CRP's OOP Wraithlord then stuck its toe in cover."