Maya plug in and Mass Frame in Physics

Other Standards COLLADA
1

Hi,

I am using Maya 2008 and I just found that when I tried to set the Center of Mass, the result is not exported at all. For example, I changed Center of mass as 2.000, 3.000, 4.000 in rigidBody1 but after export, I can not find anything change in <mass_frame>, which is identity. Did I misunderstand meaning of <mass_frame>?

Thanks in advance!

Here is my dae content:
In <physics_model>


      <rigid_body name="rigidBody1" sid="rigidBody1">
        <technique_common>
          <dynamic>1</dynamic>
          <mass>1</mass>
          <mass_frame>
            <translate>0 0 0</translate>
            <rotate>1 0 0 0</rotate>
          </mass_frame>
          <instance_physics_material url="#rigidBody1-material"/>
          <shape>
            <hollow>true</hollow>
            <instance_geometry url="#pCubeShape2"/>
          </shape>
        </technique_common>
      </rigid_body>

In <physics_scene>


        <instance_rigid_body target="#pCube2" body="rigidBody1">
          <technique_common>
            <angular_velocity>0 0 0</angular_velocity>
            <velocity>0 0 0</velocity>
            <dynamic>1</dynamic>
            <mass>1</mass>
            <mass_frame>
              <translate>0 0 0</translate>
              <rotate>1 0 0 0</rotate>
            </mass_frame>
          </technique_common>
        </instance_rigid_body>