Color Lookup Table via Dependent Textures

Hi there,
I am writing a volume renderer and would like to use each of the volume’s intensity value as an index to lookup into a 1D color table(each element is of type RGBA). As I m working on the GeForce3, I would like to achieve post-classification , so paletted textures (which does pre-classification) does not provide good enough quality.
I heard that the post-classification can be done through dependent textures. I have tried the following

  1. tex 0 - bind 3d texture
  2. tex 1 - bind 256x1 texture;, use AR dependency; previous input is tex 0.
    but am getting the wrong results.
    I think my mistake lies in not encoding the color table in a 2d texture such that the tex coord (A,R)from tex 0 would index nicely as it would in the 1D texture. So how can the 2d texture be properly encoded ?
    I have read in the forum that GL_DOT_PRODUCT_TEXTURE_2D_NV is involved. If so, how it is used to solve my problem?

Please ignore my question.
I found out my mistake.
A stupid one.