you need vec_for_bone and ent_bonemove
first of all i would set each frame the orgin of the T-shirt to the one of the player.
then you save the bone-position of the bones you want to move and the positions of the bone you want to use as target postion(the one of the player)
then you callculate the difference between the t-shirtbone position and the target bone position
at last you move the T-shirt-bone with this diggerence VECTOR
muffel hope you can understand this
