I've been trying to port models over from XPS to SFM through Blender for a while now, and something always seems to stump me. So I saw someone point these guys out and thought, "Fuck, I can do that!" So I did. Let me know if you run into any trouble, but they're pretty simple.
Evidently the person who made these doesn't want credit, but a simple google search will bring them up. So thanks, person who doesn't want credit! I give you none!
Update! Here's a rig. Should work fine. Lemme know if it don't.