You really need to wait for 2.3 for this combination. With the reduction of Hunter range to 1-5 yards, it would be easy.

Even with your 3rd toon, just put the paladin on follow of the warrior and the hunter on follow of the paladin. Charge your target with the warrior (your main), and immediately turn around and "back into it". Now the warrior and paladin are on either side in melee range and the hunter should be far enough away to shoot. This is how I get my rogue to backstab mobs my shaman is tanking.