[vtkusers]vtk Vetor file format question

[lpf]

Hi
  I am dealing with a heat vector raw data, it is float type,
its size is 256*128*128, spacing is 0.78 0.39 0.39,
now I want to hadle it with MayaVi, so I need convert
the format to .vtk. Now I add a header in the file,
But when I read it with MayaVi, pop up a error
*****************************************
ERROR: In C:\aap\src\VTK-4.4\IO\vtkDataReader.cxx, line 793
vtkStructuredPointsReader (0x0694BED0): Unsupported point attribute type: vector for file: 
D:/tensor.vtk
*****************************************

    The following is my header, what's wrong? structured point
can contain vector format, right?

--------------------------------------------
# vtk DataFile Version 3.0
created by writeVTK
BINARY
DATASET STRUCTURED_POINTS
DIMENSIONS 256 128 128
ORIGIN 0 0 0
SPACING 0.39 0.78 0.78
POINT_DATA 4194304
VECTOR image_data float
LOOKUP_TABLE default
--------------------------------------------
   By the way, if I want to deal it myself, display the heart
with arrow shape, which classes I need?


Best Regards
lpf