Help with Ripping Poses/Animations ?

Hi there,

I just came back to SL, after being away for quite a long time.
I always liked ripping poses and animations, yet now I seem to run into a weird problem lol

First of all, I use Darkstorm or Hydra to rip the poses or animations I like, and same them to the .bvh format.
So far no problem yet....
However, when I try to import them, I noticed that the upper body is working perfectly, but the lower body (waist down to legs and feet) is not.
In fact the lower body isn't moving or posing at all....

So does anybody has a clue on what I might be doing wrong ?
Or how to solve this problem ?

Thank you very much :)