BVH Export includes strange mesh twists

I’ve been working to create a workflow for exporting animations to Arma 3. I’ve gotten quite far (succesful import of handmade animation into the game) but now I’m trying to accomplish a much more advanced goal.

using NI-mate and Blender, I’m trying to live mocap in blender so I can export more detailed animations. this is due to the fact that retargeting BVH’s to the Arma skeleton has caused hassles to no end (insane, nightmarish twisting and stretching)

I’ve been able to retarget the Arma 3 skeleton to the NI mate mocap rig, but now I’m getting very similar twists, including a tornado like twist in the midsection. I’ve tried all sorts of fixes but I’m just not seeing where this problem is coming from! anyone willing to help teach a fledgling Blenderer would be greatly appreciated as there’s a whole community of modders for this game just dying for a simplified method of creating animations. (Arma is the game DayZ was a mod of)

my skype is Papa.smokapotamus and I’m on all the time. even if you just have some ideas, hit me up and let me know PLEASE, I’ve been fighting with this for about 2 weeks now and I do not want to make all the animations for our mod by hand (very tedious)

OH before I forget, I do my animation on my skeleton in blender, then move it into Oxygen (the Arma modding software, now just called Arma tools object builder) prior to putting on any mesh. I could also use some help in how to put this skeleton into the mesh and see if the problem exists in blender as well

if anyone could help me out I would be tremendously appreciative.