FBX animation(legacy) import error(OK in FBX Viewer)

I export a 3dsmax animation to FBX, then import FBX animation(Legacy) into Unity3d, and found only one of the bones("Bip01 Pelvis_Bone04") do not have animation. All other bones have animation, including the parent and the child of "Bip01 Pelvis_Bone04". (so i guess it has nothing to do with skin).

And more, the FBX can be opened in FBX viewer, and the animation plays all ok. ( download at http://fbx.clockstone.com/)

Anyone who has got the same problem please help :)