[Openspace] structure of gwt files

[Jozsef.Fabian at office.ksh.hu]

Dear list, 
I would like to modify the weights calculated by GeoDa based by centroid
distances with my own weights (travel times) calculated by Network
Analyst in ArcView.
I have the full matrix, and I would like to convert my weight matrix to
GWT format to use in GeoDa. So I would like to ask the format of the gwt
file, namely the first parameter line of the file. 
I guess the second parameter is the number of cases, then the shape file
name and the name of the key field, but what is the first number (0 in
my weights file)?
Is the 9 space spacing cruicial between the second and third column, or
there enough only one blank space between the columns?

p.s. I know, I could use R spdep, but I would prefer to write my little
conversion program to make gwt files directly from ArcView.

Thank you for your help
Jozsef Fabian