right click the bres that the model is in, add new animation. now right click the animation and say add new bone sequence. right click bone sequence, name it the first bone of the mld0. now right click the model > preview. expand the menu on the right and left. On the right click the animation you just made. on the left click the bone you named the bone sequence. now edit the scale of the bone on the right side below the animation stuff. you'll also have to edit the collision data, so after you have it scaled down to a size you want it at, click off of the animation on the right. now edit the scale again. this will change the T-pose. now you can have the appropriate scale in the collision editor
collision tutorials
if you have any questions, yeh