[ptx] Hugin : parameters for correction of chromatic aberration

[YMI2]

Hello,

In the panoramatools gimp plugin, when I want to correct  an image for
transversal chromatic aberration,  I used radial shift correction with
these parameters (corresponding to my lens) :
r_src = axr_dest^4  + bxr_dest^3 + cx r_dest^2 + dxr_dest
            a        b   c    d
red :     0.005  -0.022  0  1.0174
green :   0.005  -0.022  0  1.017
blue :    0.005  -0.022  0  1.0174

I want to use Hugin to do the same correction on 16-bit tiff images. 
 -> it's ok for the a, b and c parameters, but what about the d one ?
Does it correlate with the degre of view v parameter ? If so, how ?
 -> there seem to be no way to correct each color with different
parameters as in the panotool plugin. Is it planned to include this for
later release ? For now, I must first decompose in 3 gray images, do the
correction separately in hugin and then recompose. 

Thank for any help.

Yanick