I'd use the FEL like a big forklift, with a couple wood posts secured to your loader vertically -- 4x4s or maybe 2x4s. Attach a cross piece at 11 feet when the FEL is in the raised position. Lift one truss onto the cross piece from the ground by hand, secure it, lift and drive into position. I'd probably remove the loader bucket and bolt the wood posts directly to the FEL frame. But you might be able to figure out a way to rest them in the bucket and tie them securely to the frame.