The bones show up in scene explorer and the SDK says,
Created constraint: IK with definition: Inverse kinematics
Don't know how that's going to work out. Ill post whatever I find out.
Oddly, when importing from the SDK there's an extra bone with no name detail at the bottom of the list. That bone does not exist in the blender outliner. I deleted the IK bones and removed the modifiers and imported them again and it was still there. I suspect another SDK3.1 stable bug.