DataSetmapper + LookupTable : hide range

Hi friends,

I have a vtkUnstructuredGrid containing triangles and points data as scalars.
I’m displaying it with a vtkDataSetMapper linked to a vtkLookupTable.

Here is the resulting display :

Now what I want to do is “clip” this display, to hide values that are outside of a given values range.
Obviously I can use :
vtkLookupTable SetTableRange(min, max)
SetBelowRangeColor(1, 1, 1, 0)
SetAboveRangeColor(1, 1, 1, 0)

Here is the result :

Has you can see, the values above MAX are hidden.
But the entire ColorMap has been offseted, giving colors that are different from the 1rst shoot !
What I want is preserving the initial colors (ie. from the full ranged LookupTable) , but hiding out of range values.

Any clue ?
Thanks !

Of course I could do that geometrically with a double vtkClipDataSet (one for Min on for Max), but this would be totally overkill !