Grabbing a ragdoll by specific bone

Im trying to grab a ragdoll by a specific bone with my leap motion. I tried to use the line trace BP to get the actor and bone reference. but im not able to attach the ragdoll to my hand, the only thing im able to do is attaching the actor while hes not simulating physics, but i want the physics to simulate while beeing attached to my hand.
does anyone know how i could do this?